#37139 proposed 2025 AS rule set

The Club may alter or adjust certain specifications to equate competitive potential.
B. INTENT
It is the intent of these rules to allow modifications useful and necessary to construct a safe, more
reliable, competition automobile. Other than those items specifically allowed by these rules, no
component or part normally found on a stock example of a given vehicle shall be disabled, altered, or
removed. Cars need not be eligible for state licensure or registration.
1. The competitiveness of any car in American Sedan shall not be guaranteed. Adjustments may be made
to all vehicles to achieve a Balance of Performance, BOP.
Restricted Preparation Cars Only: Restricted Preparation American Sedan automobiles shall, at
all times, be in compliance with the specifications contained within their factory Shop/Service
Manual(s) except as modified by these rules. Factory Shop/Service Manuals may come in the form
of printed material, microfiche, CDs, DVDs and/or Internet access to manufacturer sponsored web-
based data- bases. It is the responsibility of the competitor to provide this information upon
request from any SCCA official and to provide the electronic device capable of accessing the data for
compliance verification. Failure to provide some form of the Factory Shop/ Service Manual upon
request is adequate for disqualification from any event.
C. SPECIFICATIONS
1. To maintain the restricted basis of American Sedan, updating and/or backdating of components is
only permitted within cars of the same make/model and listed on a single American Sedan
Specification line. Any updated/backdated components shall be substituted as a complete assembly.
No interchange of parts between assemblies is permitted, and all parts of an assembly shall be as
originally produced for that assembly. No permitted or alternate component or modification shall
additionally perform a prohibited function.
2. Cars are classified by year, make, model and/or engine displacement (see Section E., “Car Classification”).
a. Restricted Preparation American Sedan cars must provide their Vehicle Identification
Number (VIN), upon request from any SCCA official, for the purpose of identifying
the year in which the car was built. The VIN number shall not be used for any other
purpose.
9.1.6. AMERICAN SEDAN CATEGORY
b. The SCCA shall specify the minimum weight for each classified car, as qualified or
raced, with driver. Ballast is permitted.
c. Cars potentially eligible for Restricted Preparation may be required to run in Touring
for at least two years before being classified in American Sedan. Cars not classified in
Touring will be considered, on an individual basis, when adequate information is
available to determine correct specifications.
d. Where Factory Specifications are absent or unclear, SCCA may establish an acceptable
dimension and/or tolerance from known stock parts.
e. All rules referencing OEM parts, unless specified in these rules, must be unmodified OEM
parts.
b. AUTHORIZED MODIFICATIONS
The following modifications are authorized on American Sedan Category cars. It is not permitted to make
changes, alterations, or modifications to any component produced by the manufacturer unless specifically
authorized by these rules or required by the GCR. No permitted or alternate component or modification shall
additionally perform a prohibited function. Replacement parts may be obtained from sources other than
the manufacturer provided they are exact equivalent of the original parts. The intent of this rule is to
allow the competitor to obtain replacement parts from standard industry outlets, such as, auto parts
distributors, rather than from the manufacturer. It is not intended to allow parts that do not meet all
dimensional and material specifications of new parts from the manufacturer, unless otherwise allowed
in these rules.
a. Engine (additional specs., see Section F – Engine Build Sheets)
i. Air Induction System:
a. Full preparation cars only:
a. All cars shall fit the approved carburetor and manifold. The approved manifold may
be ported and polished, and exhaust crossover may be blocked, but its design and
configuration shall not be altered in any other way. The lowering of or boring of
holes in the center divider is prohibited. Removal or obliteration of the manifold
part number is prohibited Any external throttle linkage to the carburetor may be
used. Choke mechanisms, plates, rods, and actuating cables, wires, or hoses may
be removed. No removal or alteration of the carburetor air horn is permitted.
All air entering the intake tract shall pass through the carburetor air inlet.
b. An open-sided, closed-top air cleaner assembly, with a maximum diameter of 16
inches, with a filter element having a maximum diameter of 14 inches and a maximum
height of 3 inches is required.
c. Filter element material is unrestricted.
d. Velocity stacks, ram air, cowl induction, shrouding or ducting of air to the air cleaner
or carburetor are not permitted.
b. Restricted preparation cars only:
a. All unmodified OEM induction system components (such as, but not limited to: air
cleaner assembly (less filter element), all hoses connecting the air cleaner assembly to
the throttle body, throttle body, and intake manifold) must be maintained. All air
entering the intake tract shall enter through the OEM throttle body.
b. Non-OEM Cold air induction systems are prohibited unless indicated on specification
line.
c. Air filter element material is unrestricted.
d. Restrictor plates may be required. Refer to vehicle specification line.
ii. Fuel Pumps/Lines:
a. Any fuel pump(s), fuel pressure regulators, or filters may be used and may be
relocated, but shall not be located in the driver/passenger compartment. If a mechanical
pump is removed, a blanking plate may be used to cover the original mounting location.
b. Fuel line(s) may be replaced, relocated, and given additional protection. If the relocated
line(s) passes through the driver/passenger compartment, it/they shall be metal or metal
braided, and shall be securely fastened.
iii. Fuel Delivery:
a. Full preparation cars only:
a. Only the approved carburetor (Holley #4776, 600cfm 4bll), insulator (Holley #108-
12), and manifold (Edelbrock Performer RPM #7101-General Motors / #7121-
Ford/Mercury) shall be fitted to cars. The carburetor shall be identified by the
numbers “4776”. Additional numbers stamped on the horn section of the carburetor,
such as “-X” (indicating the die lot number for that carburetor) and “XXXX” (up to 4
digits indicating the day of the year the carburetor was produced along with the year in
the decade it was produced) shall not be used to identify the carburetor. Two carburetor
base gaskets (each base gasket can be no thicker than .125 inches) may be used, one
on each side of the insulator.
b. Other than as provided for in these rules, the carburetor shall not be modified in any
way. Any carburetor jets, air jets, accelerator pump, pump cam, and accelerator pump
nozzles may be used. Any power valves, metering blocks, and floats may be used.
No venturi (including secondary or auxiliary) shall be modified in any way, but they
may be aligned. Idle holes may be drilled in the throttle plates (butterflies). Any
butterfly attach screws can be used. Carburetors may be modified to allow “four
corner” idle adjustment. A Holley 600 carburetor test gauge kit, such as, BLP Racing
Products Kit 7862 (with the exception of Combined Throttle Shaft and Plate gauges
78623P and 78623S), may be used to validate compliance of the carburetor (Note
that the SCCA may use other kits not listed here, visual inspection, and comparison to
SCCA supplied Holley 600 carburetors). Vent tubes may be modified or replaced and
must be no taller than 2.0” when measured from the circular air cleaner mounting
surface on the carburetor to the topmost part of the tubes. The vent tubes shall not
pass through the air cleaner. The vent tubes shall not be connected to each other.
Boosters must be shaped as shown fig. g below:
b. Restricted preparation cars only:
a. OEM fuel injectors and fuel rail assembly must be maintained. To reduce fuel fire hazard,
OEM fuel rail inlet and outlet (return) ports may be changed to allow alternate fittings. No
other changes to the OEM fuel rail assembly are permitted.
b. The engine management computer or ECU may be altered but not replaced. All
modifications shall be done within the original housing. ECUs must be able to
communicate through the stock OBD reader port.
iv. Exhaust emission control:
a. A.I.R. (Air Injection Reaction) pumps, associated lines, nozzles, and other electrical/
mechanical emission devices may be removed. If such items are not removed, they shall not
be modified in any way. If EGR devices/nozzles are removed from a cylinder head or manifold,
any holes remaining shall be completely plugged.
b. Catalytic converter(s) may be removed.
v. Exhaust:
a. Full preparation cars only:
a. Replacement exhaust manifolds, or “headers,” may be used. Cylinder head mounting
flange(s) shall be no thicker than 0.375 inch, and tubing diameter shall be no greater
than 1.625-inch O.D., measured at any tube location one (1) inch from the flange to the
collector.
b. Exhaust after the manifolds/headers must meet the below requirements but is otherwise
unrestricted.
i. No exhaust pipe(s) shall pass over the engine, bellhousing, or transmission.
ii. Exhaust shall exit behind the driver and shall be directed away from the car body. A
suitable exhaust muffling system may be necessary to meet sound control
requirements.
b. Restricted preparation cars only:
a. OEM exhaust manifolds must be maintained unless indicated on a specification line.
b. Oxygen sensors may be removed and plugged.
c. Exhaust after the manifolds must meet the below requirements but is otherwise
unrestricted.
i. No exhaust pipe(s) shall pass over the engine, bellhousing, or transmission.
ii. Exhaust shall exit behind the driver and shall be directed away from the car body. A
suitable exhaust muffling system may be necessary to meet sound control
requirements.
vi. Ignition System:
a. Full preparation cars only:
a. Any ignition system which utilizes the distributor for spark timing and distribution is
permitted. Any distributor that requires no modification to the engine may be fitted.
Internal distributor components and distributor cap may be substituted.
b. Crank fire ignition systems are prohibited.
c. Any spark plugs, single coil, and ignition wires may be used.
d. Ignition timing is unrestricted.
b. Restricted preparation cars only:
a. OEM or factory equivalent ignition system must be utilized for detection and distribution.
b. OEM or factory equivalent coils must be utilized.
c. Any spark plugs and ignition wires may be used.
d. Ignition timing is unrestricted.
vii. Battery:
a. Any 12-volt battery may be used.
b. The battery may be relocated as per GCR section 9.3 Batteries.
c. Additional battery hold down devices may be used and are strongly recommended.
viii. Camshaft/Valvetrain:
a. Full preparation cars only:
a. The camshaft may be replaced with a unit of any origin meeting specified maximum lift
(see Section F – Engine Build Sheets), measured at the valve with zero lash.
b. Cam timing, timing chains, woodruff keys, dowel pins, and sprockets are unrestricted.
Double row chains may be substituted for single row chains. Timing belts and gear driven
timing systems are prohibited unless fitted as original equipment.
c. Valve lifters shall be of the solid (flat tappet) type only. Roller, hydraulic, or “mushroom”
lifters are prohibited. See Section F – Engine Build Sheets for additional specifications.
d. Valve springs are unrestricted except that they shall be made of steel. Heads may be
machined to accommodate any valve spring. Valve spring retainers and keepers are
unrestricted.
e. Rocker arms may be replaced with any rocker arm. Shaft mounted rocker arms are
permitted using a minimum of eight shafts. Valve train stud girdles are allowed.
f. Pushrods may be replaced with any pushrods of steel (ferrous) material.
g. Valve covers are unrestricted.
b. Restricted preparation cars only:
a. OEM camshaft and valvetrain components must be utilized based on vehicle year and
model. Updating and/or backdating within a specification line is permitted.
b. All camshaft/valvetrain hardware shall be installed/timed in conformance with those
specifications and procedures outlined by the vehicle’s manufacturer.
c. Alternate camshafts may be specified for performance equity. See specification line.
d. Valve covers are unrestricted.
ix. Oiling system:
a. Oil pans, pan baffles, scrapers, and windage trays, oil pickups, lines, and filters are
unrestricted.
b. A pressure accumulator/” Accusump” may be fitted.
c. The location of the filter and accumulator are unrestricted, but they shall be securely
mounted within the bodywork.
d.All oil lines that pass into or through the driver/passenger compartment shall be metal or
metal braided hose.
e.Engine oil and oil additives are unrestricted.
f. Oil catch tanks are permitted. All engine breathers or vapor recirculation lines, if disconnected,
shall vent to a catch tank of one (1) quart minimum capacity. Such catch tanks shall not
be mounted in the driver/passenger compartment.
x. Accessory Drive:
a. Full preparation cars only:
a. Engine drive belts and pulleys may be replaced with any non-tooth driven belt and
appropriate pulleys for the purpose of component RPM reduction.
b. Any mechanical (non-electrical) water pump may be used provided it is mounted in the
original position.
c. Any belt driven, mechanical power steering pump and any alternator may be used. They
must mount to the front of the engine. Remote reservoirs maybe added.
d. Any power steering and/or alternator brackets may be used if they perform the same
mounting function as the originals.
e. Air conditioning systems may be removed in whole or in part.
b. Restricted preparation cars only:
a. Engine drive belts and pulleys may be replaced with any non-tooth driven belt and appro-
priate pulleys for the purpose of component RPM reduction.
b. OEM or factory equivalent alternator, power steering pump and water pump may be used
for repair purposes.
c. Air conditioning systems may be removed in whole or in part.
xi. Engine Components:
a. Full preparation cars only:
a. Engine block shall be cast iron as produced by the vehicle’s manufacturer and must meet
the requirements in Section F – Engine Build Sheets.
b. Main cap girdles may be fitted.
c. Any aluminum replacement piston with three piston rings may be used. See Section F –
Engine Build Sheets for additional specifications.
d. Piston rings are unrestricted.
e. Balancing and “blueprinting” of the engine assembly are permitted. Lightening of parts
beyond the minimum material removal necessary to balance is prohibited.
f. An alternate, commercially available, vibration dampener may be fitted.
g. Cylinder head to intake/exhaust manifold port matching is permitted. No material shall
be removed from or added to the cylinder head(s) further than one (1) inch in from the
manifold to cylinder head mounting face(s). External dimensions of the cylinder head or
intake/exhaust manifold shall not be reduced to facilitate internal porting. Cutting (and
subsequent welding of) the intake manifold to facilitate internal porting is not permitted.
h. The throat area of the port consists of a single cut up to a maximum 90-degree angle at
the very bottom of the steel valve seat as it transitions to the aluminum or cast-iron
casting below (“Throat Cut”). It is permitted to plunge cut the throats in order to correct
for core shift that is commonly found in many cylinder heads. This cut cannot extend
further than 1.100 inches below from the top of the ferrous valve seat. There can be no
tooling or machine marks in the head below this point. The area where the cut meets the
floor of the cylinder head port cannot be blended by hand, machined, or chemically
processed to create a smooth transition at this point. No aluminum or cast iron in the bowl
area (other than that specified for the plunge cut) or the ports may be removed, added, or
manipulated for any reason. It is understood that many heads may look slightly different
from bowl to bowl due to casting irregularities. No material may be removed or added from
the short turn radius in the port. No material shall be removed, added, or manipulated in
any area of the heads beyond the 1 inch in port matching. The heads shall not be blended by
hand, machined, or chemically processed for any reason (including, but not limited to) to
create a smooth or resurfaced appearance. The heads shall not be cut (and subsequently re-
welded) for any reason. Any modification of the cylinder head beyond that permitted in
this section and Section F. (Engine Build Sheets) is prohibited. See Section F – Engine
Build Sheets for additional specifications. Where possible, the SCCA will specify
dimensions. The lack of dimensional specifications does not negate the restrictions outlined
here with respect to the heads and intake manifold.
i. Valve guide material is unrestricted.
j. Milling of the cylinder head to increase compression ratio is permitted.
k. Any or all valve seats may be replaced. Valve seat material must be ferrous.
l. The combustion chamber may be repaired or modified in the area shown in Section F –
Engine Build Sheets, Drawing 2 to repair or prevent pitting or damage between the intake
and exhaust valves. For this repair or modification, it is permissible for the valve seats
to contact each in the area shown in Section F, Drawing 2. This repair/modification may
serve no other purpose.
m. Only stock, steel, or stainless-steel intake and exhaust valves are permitted. Titanium
or titanium alloy valves are not permitted. Valve seat specifications shall comply with
Section F – Engine Build Sheets, Drawing 1. Valve length and valve stem installed height
is open. Any valve seal may be used.
n. A valve job will consist of 3 valve angles only not including the throat cut angle. Each of
these valve angles is open. The widths of the valve angles on the head and on the valve
are open. The maximum diameter of the cut in each valve seat is .250 inches greater
than the diameter of its valve head. All valve cuts must be concentric with the valve
stem. Additional valve specifications are listed in Section F – Engine Build Sheets. Valve
seat specifications shall comply with Section F – Engine Build Sheets, Drawing 1.
o. Aftermarket starters mounted in stock location are permitted.
p. Engine gaskets are unrestricted.
q. Motor mounts are unrestricted. Engine must remain in the original, or approved location.
b. Restricted preparation cars only:
a. OEM engine components must be utilized based on vehicle year and model. Updating and/ or
backdating within a specification line is permitted. Replacement parts may be purchased from
alternative standard outlets such as parts stores, provided they are equivalent of the stock
OEM part.
• Replacements parts include:
• Pistons and rings
• Bearings
• Oil Pump
• Starter
• Seals
• Gaskets
b. OEM oversized pistons or factory equivalent may be used for repair purposes (max .040
inches over the bore size listed in vehicle’s specification line allowed).
c. OEM oversized piston rings or factory equivalent may be used for repair purposes.
d. OEM oversized bearings or factory equivalent may be used for repair purposes.
e. Engine repair procedures shall be performed utilizing OEM procedure or Factory Service
bulletins. Where Factory Service Manual measurement specifications for engine
components may conflict with assembled Factory Service Manual specifications for
performance (such as, but not limited to, compression ratio), the performance
specifications shall be the measurement used for compliance. The SCCA strongly
encourages the measurement of performance specifications after engine assembly and the
adjustment to compliance, if needed, through the use of items listed in 9.1.6.D.1.k.2.a.
f. Balancing is allowed. Removal of material solely for the purposes of balancing is permitted.
g. Motor mounts are unrestricted. Engine must remain in the original location.
h. Maximum allowed compression ratio for all restricted preparation cars is specified in the
vehicle’s specification line.
xii. Flywheel/Clutch:
a. Full preparation cars only:
a. Any flywheel of stock diameter and weighing a minimum of 15.0 lbs. with ring gear may
be used.
b. Any clutch disc and pressure plate of stock diameter may be used.
c. Pressure plate/clutch cover assembly shall be ferrous only and shall bolt in the original
stock mounting location.
d. Balancing of the flywheel/clutch cover assembly/pressure plate is permitted.
e. SFI 1.1 or 1.2 spec flywheel and clutch are allowed as long as they meet the above
specifications. Method of clutch actuation is unrestricted.
b. Restricted preparation cars only:
a. OEM or factory equivalent flywheel, clutch disc, pressure plate, and throwout bearing
must be utilized.
b. OEM method of clutch actuation must be maintained. i.e. hydraulic or mechanical with
concentric or lever style throwout bearing.
xiii. Misc. Engine Components:
a. All engine components not otherwise listed in these rules shall meet factory specifications
for stock parts.
xiv. Cleaning:
a. Engine parts, including, but not limited to, heads, intake manifolds and carburetors, may be
cleaned using usual methods (e.g., bead blasting, soda blasting, Scotch Brite pads) as long as
part dimensions are not altered.
xv. Coatings/Paint:
a. Unless otherwise restricted within the AS rules, paints and coatings are permitted on
drive- train components except for the following locations: internal engine block surfaces,
internal cylinder head surfaces, internal intake manifold surfaces, and internal carburetor
surfaces.
b. Engine Cooling System:
a. Radiator:
i. Any radiator may be used, provided it can be mounted in the original location and
requires no body or chassis modifications to install.
ii. Catch and/or expansion tanks may be added or substituted.
iii. Engine coolant fluid is unrestricted.
iv. Coolant/heater hoses and clamps may be substituted. Heater hoses may be plugged.
Heater water control valve(s) may be added or substituted.
v. The entire heater assembly may be removed. This includes all hoses, lines, ducts,
coils, and controls. Any resulting holes in the firewall must be plugged or covered.
vi. Thermostats may be modified, removed, or replaced with blanking sleeves or
restrictors.
vii. Screens may be mounted in front of the radiator and/or oil cooler(s) and must be
contained within the bodywork.
b. Coolers:
i. Engine and power steering oil cooler(s) may be added or substituted.
ii. Location within the chassis is free, provided that it/they are not mounted within
the driver/ passenger compartment.
c. Cooling Fans:
i. Any cooling fans may be used. Cooling fans may be removed.
ii. Electrically operated fans with manual or automatic actuation may be fitted.
iii. Transmission/Final Drive:
1. Transmission:
a. Full preparation cars only:
i. Any H-Pattern 4 or 5 speed transmission is permitted with the gear ratios listed on
the vehicle spec line (with a tolerance of +/- .05 per gear). 4 speed transmissions
must match either 4 speed gear ratios listed on their specification line or one of the
car’s specification line 5 speed gear ratio sets for gears 1 through 4, with a tolerance
of +/- .05. Sequential shifting transmissions are prohibited. Pneumatic, hydraulic, or
electric actuation of the gear shift mechanism is prohibited. Transmissions that use a
gear engagement mechanism different than stock type (e.g., circular, beveled) are
prohibited. Face-tooth engagement gearboxes (e.g., dog rings) are permitted at a 50
lbs. weight penalty. Any first gear ratio greater than 2.5 is permitted.
ii. Any conventional H-pattern, non-sequential shifter may be used.
iii. Transmission mounts are unrestricted.
iv. Transmission lubricants are unrestricted.
v. Transmission coolers are permitted. Dry Sump transmission coolers are not
permitted.
b. Restricted preparation cars only:
i. OEM or Factory equivalent transmission components must be utilized. Updating
and/or backdating within a specification line is permitted.
ii. Transmission repair procedures may be performed utilizing OEM procedures.
iii. Any conventional H-pattern, non-sequential shifter may be used.
iv. Transmission mounts are unrestricted.
v. Transmission lubricants are unrestricted.
vi. Transmission coolers are permitted. Dry Sump transmission coolers are not
permitted.
2. Driveshaft:
a. Full preparation cars only:
i. OEM driveshafts may be replaced with any one-piece driveshaft of steel or
aluminum construction.
ii. The driveshaft may be modified to fit alternate differentials and/or transmissions.
iii. Driveshaft loops are permitted/recommended.
b. Restricted preparation cars only:
i. OEM driveshafts may be replaced with any one piece driveshaft of steel or
aluminum construction.
ii. Driveshaft loops are permitted/recommended.
3. Rear Axle/Final Drive:
a. Full preparation cars only:
i. Any OEM rear axle assembly is permitted, provided it was available in the listed
vehicles contained within the specification line.
ii. Ford 9” rear axles are permitted in all cars. Center section shall be of ferrous
material.
iii. Dana 44 axles are permitted in all cars.
iv. Any final drive ratio is permitted.
v. Any limited slip or locked differential is permitted.
vi. C-clip eliminators are permitted.
vii. Full floater axles are permitted.
viii. Aftermarket or modified rear differential covers are allowed.
ix. Differential coolers are permitted. Dry Sump differential coolers are not
permitted.
x. For any rear axle assembly, welding of the rear axle tubes is permitted.
b. Restricted preparation cars only:
i. Any OEM rear axle is permitted, provided it was available in the listed vehicles
contained within the specification line.
ii. Any final drive ratio is permitted, provided it fits the allowed stock differential
housing without modification to the housing.
iii. Any limited slip or locked differential is permitted.
iv. Aftermarket or modified rear differential covers are allowed.
v. Aftermarket axle shafts and bearings are allowed.
vi. Differential coolers are permitted. Dry Sump differential coolers are not permitted.
vii. C-clip eliminators are permitted.
viii. For any rear axle assembly, welding of the rear axle tubes is permitted.
iv. Suspension:
1. Ride Height- Minimum ride height is five (5) inches, to be measured without driver at the lowest
point of the sheet metal rocker panel, but not to include welded seams, stock ground effects clad- ding,
or fasteners.
2. Springs and Shock Absorbers:
a. Springs of any origin may be used, provided they are of the same number and type as
originally fitted and they must be installed in the original location. Front suspension coil
over springs and shocks are prohibited, unless fitted as original equipment. Rear spring
relocation to the shock is permitted.
b. Any shock absorbers may be used, provided they attach to the original mounting points on
the chassis. The number of shock absorbers shall be the same as stock. Remote
reservoir shock absorbers are permitted. The location of the reservoir is unrestricted.
No shock absorber may be capable of adjustment from within the cockpit or by any
other means, such as, but not limited to, any electronic, computer, or feedback control
systems while the car is in motion. Magnetic shocks are not permitted.
c. Strut equipped cars may substitute struts and/or may use any insert. On cars where the
strut assembly also serves to locate a spring, the lower spring seat ride height location
may be altered from stock. Spacers, including threaded units with adjustable spring
seats, may be used.
d. Spacers, including threaded units with adjustable spring seats (weight jacks), may be
used with coil springs. If spacers are used, they shall be located on and shall be
permanently attached to existing chassis or suspension structure but shall not serve
as a reinforcement to that structure. Material may be removed from the upper or
lower spring seat to facilitate installation of the spacers. Material may be removed from
the chassis, but not the bodywork, to facilitate adjustment of the spacers.
e. Limiting straps to preclude a spring from becoming dislodged are permitted.
3. Suspension Control - Any anti-roll bar(s), traction bar(s) and rear upper control arms or like devices,
Panhard rod, or watts linkage may be added or substituted, provided its/their installation
serves no other purpose. The mounts for these devices may be welded or bolted to the
structure of the vehicle. No suspension control mount or component shall be located in the
trunk or driver/ passenger compartment unless installed by the manufacturer as original
equipment. No suspension control component may be capable of adjustment from within the
cockpit while the car is in motion.
4. Suspension Mounting Points:
a. Cars may adjust camber by the use of eccentric bushings at the lower control arm pivot
points, by the use of eccentric bushings at the upper suspension control mounting
points, and/or by use of slotted adjusting plates at the upper suspension mounting
point. If slotted plates are used, they shall be located on existing chassis structure.
Material may be added or removed from the upper suspension mounting point to
facilitate installation of adjuster plate.
b. Rear camber shall be no more than 1/2 degree negative per side. If equipped with IRS,
rear camber shall be no more than 2 degree negative per side.
c. All forms of suspension may adjust caster by means of shims or eccentric bushings. All
cars may adjust caster at the upper suspension mounting point/plate.
d. One (1) stay rod may be fitted between the upper front strut/shock towers. One (1)
reinforcement bar may be fitted between each front strut/shock tower and the firewall.
e. Bushing material is unrestricted except that bushing material must be at least as stiff as
stock (i.e. equal or higher durometer rating). “Air”, foam, or other soft materials that
render the control arms ineffective, are strictly forbidden. Control arm to
spindle/knuckle ball joints must be stock or equivalent replacement. Ball joint may be
welded or positively attached. Original unmodified lower control arms (front and rear),
and original unmodified front upper control arms must be retained. Vehicles with rear
trailing arms may replace OEM arms with tubular arms. Arms must maintain stock
length and serve no other purpose than locating rear axle assembly. Pins, keys, or
weldment may be used to prevent the rotation of alternate bushings but may serve no
other purpose than that of retaining the bushing in the desired position.
f. Any rubber bump stops may be used, but their chassis mounts, brackets, etc., shall
not be altered in any way. Rubber bump stops may be removed.
g. Pick-up points on the rear axle housing may be relocated. The removal and/or
replacement of the rear suspension torque arms and upper arms is allowed. On rear
leaf spring cars: eye mounting points may be relocated, and traction bars allowed. Pick-
up points, on the chassis, for front and rear lower control arms, shocks, and springs, must
remain in the original location.
h. The use of offset steering rack bushings is permitted. Any tie rods and tie rod ends
may be used. Spindles may be machined so that tapered tie-rod end bolts can be replaced
with straight bolts.
v. Brake System:
1. Materials:
a. Brake pads, brake linings, and brake fluid are unrestricted.
b. Brake lines may be replaced with steel lines or Teflon lined metal braided hoses.
Lines/hoses may be relocated and may be given additional protection. Brake fittings, adapters,
and connectors are unrestricted.
c. Hubs shall be of ferrous material or aluminum.
d. Rotor hat shall be of ferrous material or aluminum and may be part of the hub or rotor.
e. Rotor shall be of ferrous material. Rotor shall be the same diameter and thickness as
the standard or alternate listed on the specification line for the vehicle.
f. Mounting brackets shall be of metallic material.
g. Materials may differ from above if OEM hardware is utilized.
h. Brake duct fans are permitted for cooling brakes. They shall perform no other function.
2. Components:
a. Full preparation cars only:
i. Air ducts may be fitted to the brakes, provided that they extend in a forward
direction only, and that no changes are made in the body/structure for their use.
ii. Parking brakes, mechanisms, and actuating components may be removed.
iii. One piece front or rear hub with rotor may be replaced with separate hub, rotor hat,
and rotor.
iv. Front spindles/knuckles may be modified to facilitate mounting of alternate brake
calipers. Spindle modifications shall serve no other purpose.
v. Any front caliper using four (4) or fewer pistons and using one (1) brake line per
caliper is allowed.
vi. Any rear caliper using four or fewer pistons and using one brake line per caliper is
allowed.
vii. Rear caliper mounting brackets may be substituted.
b. Restricted preparation cars only:
i. Air ducts may be fitted to the brakes, provided that they extend in a forward
direction only, and that no changes are made in the body/structure for their use.
ii. Parking brakes, mechanisms, and actuating components may be removed. OEM
brake hardware, including knuckle/spindle, caliper, rotor, hub, and associated
mounting hard- ware must be utilized.
iii. Full Preparation modifications as listed in 9.1.6.D.5.b.1 (Components) may be used
with wheel sizes listed in a Restricted Preparation car’s specification line. Maximum
rotor size for this option (front and rear) is 13.1 inches X 1.27 inches. (full prep
spec lines 10x)
3. System Control:
a. Brake system circuitry may be revised.
b. The original master cylinder may be replaced with any single or dual master cylinder
(with balance bar).
c. Any pedal assembly, including the throttle pedal, clutch pedal, clutch and brake master
cylinders, mechanical linkage, and hydraulic lines, may be used. The pedal assembly, and
master cylinders, may be relocated. Firewalls and cowlings may be modified to allow for
installation of the pedals and master cylinders. Modification must be the minimum
required to complete the installation and shall not serve any other purpose. Dead
pedal/footrest and heel stop may be added.
d. Any brake booster may be used. The brake booster may be removed. A vacuum reservoir
or booster may be added.
e. A brake-bias adjustment cable is permitted.
f. Brake proportioning valves may be used provided that they are of the inline, pressure
limiting type.
g. ABS and traction systems must be disabled. It is the responsibility of the competitor to
provide proof of system disabling.
vi. Wheels/Tires:
1. Wheels:
a. Maximum wheel diameter is 17 inches, unless otherwise indicated within the vehicle
specification line.
b. Maximum wheel width is restricted based on the following:
Vehicles with max tire size of 275mm, max rim width is 10 inches.
Vehicles with max tire size of 295mm, max rim width is 11 inches.
Vehicles with max tire size of 315mm, max rim width is 12 inches.
Vehicles with max tire size of 335mm, max rim width is 13 inches
Unless indicated within the vehicle specification line.
c. Knockoff or quick-change type wheels are prohibited.
d. Track may be changed to accommodate larger tires, provided that there is safe
tire/fender/ chassis clearance under all conditions of steer, bump, and rebound.
Wheel spacers are permitted.
e. Tire tread (that portion of the tire that contacts the ground) shall not protrude beyond
the fender opening when viewed from the top perpendicular to the ground.
f. Any wheel stud, bolt, and/or nut is permitted.
2. Tires:
a. Max tire size for all cars is 275, unless indicated within the vehicle specification line.
b. Weight penalty for increased width may be assigned within specification line.
c. Tires must conform to GCR section 9.3 Tires.
d. American Sedans must compete on DOT “R-type” road race tires. Permitted tires are
listed below. Soft “A type” autocross tires are prohibited:
BFGoodrich R1 & R1S
Goodyear DOT radial DOT R compound Hankook Ventus Z214 C51/Medium Hoosier R7
or R6 or WET/H20 or W2 Kumho Ecsta V700 series
Nitto NT01
Toyo R888, Toyo Proxes RA1, or Proxes RR Yokohama A048 or A052
Rain tires must continue to have DOT rating, except that softer compound dry tires, such as the Hoosier A7 (but not
limited to), are not permitted for use as rain tires.
The objective of this rule is to require the use of a more durable and economical tire. Performance of approved tires
will be monitored by the ASAC and those which are found to deviate from this objective may be subject to exclusion by
means of a Tech Bulletin or other appropriate communications.
Additional tires may be requested for consideration by the ASAC and may be introduced within rule change timing
cadence.
vii. Body/Structure:
1. Fenders:
a. Fenders and wheel openings shall remain unmodified.
b. It is permitted to roll under or flatten any interior lip on the wheel opening for tire
clearance.
c. Cars with plastic/composite fenders may remove any interior wheel opening lip, but
the resulting material edge shall be no thinner than the basic fender material
thickness.
d. Any non-metallic inner fender liners may be used or removed.
2. Air Dams/Spoilers:
a. A front spoiler/air dam is permitted.
b. The front spoiler/air dam shall not protrude beyond the overall outline of the body when
viewed from above perpendicular to the ground.
c. The front spoiler/air dam shall be mounted to the body, and shall extend no higher than
four (4) inches above the horizontal centerline of the front wheel hubs. No part of the
front spoiler/ air dam shall be lower than three (3.0) inches from the ground. OEM
(factory) front spoiler/air dam systems are permitted and if mounted in the stock
location, have no height restrictions.
d. The front spoiler/air dam shall not extend toward the rear of the car further than the
vertical centerline of the front wheel hubs.
e. The front spoiler/air dam shall not cover the normal grille opening(s) at the front of the
car.
f. Openings in the front spoiler/air dam are permitted for the purposes of ducting air to
the brakes, cooler, and radiator.
g. Rear spoilers or wings shall be as originally fitted or as specifically authorized on the
specification line for that vehicle.
3. Bumpers/Facias:
a. Unless authorized in these rules or stated in a spec line, all bumper covers, and metal
bumper bars shall not be modified or removed. Bumper absorbing material may be
removed.
b. Front parking/fog light assemblies may be removed for ducting of air.
4. Hood/Roof/Trunk/Rear Deck:
a. Hood and trunk pins, clips, or positive action external latches are permitted.
b. Stock hood and trunk latches may be disabled or removed; if so, some positive action
external fastening method shall be used.
c. Any hood/trunk hinges may be used. Hood/trunk hinges may be removed.
d. Under hood bracing on stock hoods, trunks, and rear decks may be modified or removed.
e. Steel, aluminum, or fiberglass hoods may include a sealed protrusion above the hood’s
external profile not to exceed 3 inches in height. Otherwise, the external profile of the
hood shall remain stock.
f. Ram air openings and rear openings must be blocked off to prevent passage of air.
g. Sunroofs, Targa tops, and T-tops are only permitted if installed by the manufacturer
of the vehicle. If installed they must be retained on the vehicle, run in the closed
position, and securely bolted in place unless the operating rails adequately secure the
panel. Glass panels are permitted.
5. Glass:
a. OEM or factory equivalent windshield is required.
b. Side windows (not including the front door windows) and rear/deck glass must be
OEM/ equivalent or clear polycarbonate type plastic material having a minimum thickness
of 3 mm. Polycarbonate windows must retain the same shape, size and location as OEM
and must be securely fastened to the car.
c. Door glass, quarter glass, and side marker assemblies may be removed. Openings left by
the removal of side marker assemblies shall be completely closed. Quarter glass (if not
removed or replaced with Lexan-type plastic material as noted in 9.1.6.D.7.e.2, or
NACA-ducts per 9.1.6.D.8.a.12) must be OEM or factory equivalent.
d. Windshield defrosters are allowed as long as they serve no other purpose.
e. Any windshield wipers, motors, arms, and brackets may be used or removed.
6. Doors:
a. The door window operating mechanism, inner door trim panel, armrest, map pockets,
and inside door latch/lock operating mechanism may be removed and the inner door
structural panel may be modified or removed.
b. The stock side impact beams may be removed when NASCAR-style door bars are
installed. Original door hinges and exterior door handles shall be retained. Doors may
be pinned, not bolted.
7. Frame/Subframe:
a. The frame or subframe shall be stock for body used.
b. The front and rear subframes may be tied together (front to rear, without crossing the
center- line of the chassis) with subframe connectors consisting of curved or straight
steel tubing (round, square, or rectangular section) with a maximum wall thickness of
0.125”.
c. Sub frame connectors may be bolted or welded to the subframes. These connectors
may extend under the floor or may extend through the floor with the floor completely
welded to this member. Seam/stitch welding is permitted.
d. A connector may be added between the left and right front frame rails forward of the front
axle centerline.
8. Weather Stripping/Seals:
a. Engine compartment, trunk, hatch, and door rubber seals or weatherstripping may be
removed.
9. Repair/Modification:
a. All chassis/structural repair, if performed, shall be in concurrence with factory
procedures, specifications, and dimensions.
b. Body repair shall be performed using every reasonable effort to maintain stock body
contours, lips, etc. Any body repair modification having as its purpose increased clearance
is prohibited.
c. Unless authorized in this rule set, alteration by adding any materials, such as, but not
limited to, tape, stickers, metal, or vinyl, for the purposes of improving aerodynamics
is prohibited.
d. The unibody may be deformed or modified to accommodate the installation of components
or other modifications allowed by these rules. The rear bulkhead may not be cut to
accommodate the installation of traction bars or rear upper control arms or like devices.
Deformations or modifications shall perform no other function.
e. All exterior and interior trim, grills, moldings, vents, badges, and screens may be
removed. Resulting holes may be covered.
viii. Driver/Passenger Compartment:
1. Interior:
a. All seats and seat brackets may be removed.
b. In those automobiles where the rear seat back provides the only solid bulkhead between
the driver/passenger compartment and an exposed stock gas tank, a metal bulkhead
completely filling the exposed seat back opening shall be installed.
c. In those automobiles where rear seat back, removal does not expose the stock gas tank
directly to the driver/ passenger compartment, a metal (only) bulkhead is optional.
d. Any steering wheel except wood rimmed types may be used.
e. Any gear shift knob may be used.
f. Gauges and instruments are unrestricted. Any instrument panel may be used.
g. Any interior or exterior mirrors may be used.
h. Sun visors, seat belts and their attaching hardware and bracketry may be removed.
i. Complete removal of interior panels is allowed in all or part.
j. Any removable covers used to cover spare tires, tools, bins, etc., may be removed along
with attaching hardware and bracketry.
k. Carpets, mats, and their insulating or attaching materials may be removed from the floor
and recesses of the cargo/trunk/spare tire area.
l. Installation of air ducts to direct air to cool the driver is permitted. Air ducts to direct
air to cool the driver can be installed behind the a-pillar. Duct and mount cannot exceed 8
inches in height by 12 inches in length. NACA-ducts may be mounted in the side
windows or quarter windows.
ix. Safety:
1. Restraint Systems:
1. Airbags/passive restraint systems shall be removed.
2. Headlights:
a. Headlight and headlight operating ancillaries may be removed.
b. All resulting openings shall be covered by solid panels of an alternate material. These
covers shall be of the same contour and plane as the original lens.
c. OEM light assemblies (i.e. foglamps, driving lights, etc.) mounted on, in or below the
bumper shall be removed. Resulting holes may be closed or used for the purpose of
ducting air to the brakes, cooler and or radiator as permitted.
3. Steering Column:
a. The steering column is unrestricted.
b. A collapsible type steering column is strongly recommended.
c. The driver’s normal seated position must not be relocated.
d. Full Preparation cars that have OEM electric steering may remove it.
4. Roll Cage - All cars must have a roll cage as specified in 9.4 Appendix I - 2007 roll cages, sections:
9.4, 9.4.1 and 9.4.4 GT Roll cages, or Appendix J – 2004 Roll Cage Rules.
x. Miscellaneous:
a. Hardware/Fasteners:
1. Hardware items (nuts, bolts, etc.) may be replaced by similar items performing the
same fastening function(s)
c. Wiring:
1. Removal of wiring associated with a component which may be removed by these
rules is permitted.
2. All non-essential wiring, switches, gauges, horns, flashers, relays, and lights may
be removed.
3. Existing wiring may be substituted.
d. Fuel Cells
1. Fuel cells must be located behind the rear axle and within 24 inches of the
standard tank. The 24 inch measurement is taken from the perimeter of the stock
and alternative fuel cell. Fuel filler location is unrestricted with installation of a
safety fuel cell.
1. E. CAR CLASSIFICATION
No automatic transmissions, turbochargers/superchargers, or convertibles are permitted in
American Sedan. Cars are classified by body style and engine displacement. NOTE: For competition in
American Sedan, Full Preparation General Motors products shall be prepared to 1982-1992
Chevrolet Camaro and Pontiac Firebird engine and transmission specifications per current
American Sedan Category Specifications. Full Preparation Ford products shall be prepared to the
79-93 Mustang engine and transmission specifications per the current American Sedan Category
Specifications.
F. ENGINE BUILD SHEETS (Full Preparation only)
1. Full Preparation
2. Crate Motor equipped full preparation vehicles.
The following “crate motors” may be utilized in Full preparation vehicles:
Ford Performance M-6007-D347SR7 engine assembly for Ford produced vehicles.
GM Performance parts CT400 P/N-19370604 or 19370604 engine assembly for GM produced vehicles.
No modifications may be made to these engine assemblies except the following listed components. All
replaced components must be replaced with components meeting existing full preparation rules. If
components are not furnished with the “Crate Motor” assembly, all additional components must meet
existing Full preparation rules:
1. Oil pan and oil pump pickup.
2. Valve/Rocker Covers
3. Distributor assembly
4. Spark plugs
5. Water pump
6. Thermostat
7. Fuel Pump
Disassembly of the engine is permitted for repair. All components must be replaced with exact OEM
replacement components.
“Crate Motor” equipped vehicles are not subject to additional weight additions due to increased
displacement. Adjustments to min weights may be made to balance performance if necessary. Refer
to specification line for minimum weight requirements.
Full Prep Engine Specs
No. of Cylinders: V-8 Bore (Max): 4.040”
Stroke (Max): 3.500” Compression Ratio: 10.30 Max.
Piston to Deck Clr.: Not to exceed 0.013” above block deck surface (zero deck)
Valve Lift: 0.5000” Max. @ 0.0000” lash Head Casting #’s: see spec lines.
2. BLOCK
Crankshaft Housing Bore: 2.4412-2.6416” Block Deck Height:
3. GM: GM: 8.9970”-9.0430”
Ford: 8.1880-8.2240”
Bore Spacing:
4. GM: 4.4000”
Ford: 4.3800”
Roller bearings of any type are not permitted for the camshaft, rod, or crankshaft bearings.
Options:
1. One-piece rear main seal adapter (with seal) may be used.
2. Cylinder block oil restrictors may be installed.
3. Block may be machined for the purpose of installing cylinder O-rings.
4. Block may be machined to true warped surfaces.
5. Block casting seam flash may be deburred.
6. Lifter bore sleeving is permitted (bronze sleeve material is permitted).
7. A maximum of two cylinders may be sleeved.
8. Steel main bearing caps and four bolt main bearing caps may be fitted provided no other
modifications are made to any approved part or specified dimension. Blocks may be machined to
accept four bolt bearing caps.
9. Alternate blocks may be used:
GM vehicles – Dart P/N SHP31161111 or World Product 084010
Ford vehicles – Dart P/N SHP31374175 or World Product 087110
5. CONNECTING RODS
Big End Bore: 2.2247-2.2398”
Pin Fit: Floating or Interference Fit
Center to Center: 6.00” Max
Material: Forged Steel / Cast Iron (No Billet)
Alternate Manufacturer: Any rod meeting the AS specs is permitted.
Options:
1. Wrist pin oiling holes may be added.
6. CAMSHAFT
Drive Type: Single or dual row chain.
Lifter Type: Solid, flat tappet
Lifter Dia: .8750” nominal
Options:
1. Camshaft thrust button may be installed.
7. CRANKSHAFT
Main Journal Dia (Min): 2.2182”
Rod Journal Dia (Min): 2.0690”
Options:
1. Any commercially available steel crankshaft (cast or forged) which meets approved stroke, journal
diameters and other specified dimensions and requirements is permitted. The minimum weight
for any steel crankshaft shall be 42 lbs.
2. Crankshaft casting seam flash may be deburred.
8. PISTON
Material: Aluminum (Cast or Forged)
Ring Configuration: 3 rings, above pin.
Dome Configuration: Any dome configuration is permitted.
Pin Diameter: .930” Max
Options:
1. Pins may be centered or offset. Offset shall not exceed factory specifications.
9. CYLINDER HEADS
Valve Job (Head): Refer to Figure 1
Intake Valve Size (Max): 1.94” Exhaust Valve Size (Max): 1.55” Port Volume (Max.): see spec line.
1. Edelbrock Performer RPM Cylinder Heads:
a. GM – P/N 608879, 608979
(Max port volume IN-190cc, EX-65.00)
Valve size 1.94 Intake / 1.550 Exhaust
b. Ford – P/N 602479, 602579
(Max port volume IN-190cc, EX-65.00)
Valve size 1.94 Intake / 1.550 Exhaust
2. OEM Cast Iron Cylinder Heads: (with a 250 lb. weight reduction).
a. GM – casting #14101081
(Max port volume IN-170.00, EX-65.00)
Valve size 1.94 Intake / 1.550 Exhaust
b. GM – casting #14014416
(Max port volume IN-168.00, EX-60.00)
Valve size 1.94 Intake / 1.550 Exhaust
c. Ford – casting # F3ZE AA, F1ZE-AA, F77E-AA V
(Max port volume IN-143.00, EX-54.00)
Valve size 1.94 Intake / 1.550 Exhaust
3. Flotek Cylinder Heads:
a. GM – P/N 102-500
(Max port volume IN-190cc, EX-65.00)
Valve size 2.02 INTAKE / 1.600 Exhaust
b. Ford – P/N 203-500
(Max port volume IN-190.00, EX-65.00)
Valve size 1.94 Intake / 1.550 Exhaust
Options:
1. Angle milling permitted on head gasket or intake manifold gasket surface(s) only.
Modification or machining of exhaust manifold surfaces of cylinder head is prohibited.
2. Intake manifold surface may be milled to match angle milled head.
3. Heads may be machined to accept pushrod guide plates.
4. Heads may be machined to accept screw-in rocker studs.
5. Heads may be machined to for the purpose of installing integral O-ring head gaskets.
6. Heat riser passage may be blocked.
7. Valve spring pockets may be machined.
Notes:
1. Absolutely no modification, machining, tooling, etc. of the combustion chambers is permitted.
10. MISCELLANEOUS
1. Direct replacement high volume/pressure oil pumps may be fitted provided that no
modification to the engine is required for their installation. Alternate oil pump drive shafts
may be fitted.
11. G. MEASUREMENT STANDARDS
Measurement standards shall be as specified in Appendix G. with the following exceptions:
Wheelbase has a tolerance of + 2”/- 1”.
In AS Spec Lines, replace with new Spec Lines as attached: