#35441 2024 Ruleset

specify the category to which they apply. The Club may alter or adjust certain specifications to equate competitive potential.
2. 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.
A. The competitiveness of any car in American Sedan shall not be guaranteed.
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.
3. SPECIFICATIONS
A. To maintain the restricted basis of American Sedan, updating and/
B. 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
9.1.6. AMERICAN SEDAN CATEGORY
originally produced for that assembly. No permitted or alternate component or modification shall additionally
perform a prohibited function.
C. Cars are classified by year, make, model and/or engine displacement (see Section E., “Car Classification”).
D. 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.
E. The SCCA shall specify the minimum weight for each classified car, as qualified or raced, with driver. Ballast is
permitted.
F. 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.
G. Where Factory Specifications are absent or unclear, SCCA may establish an acceptable dimension and/or
tolerance from known stock parts.
H. All rules referencing OEM parts, unless specified in these rules, must be unmodified OEM parts.
4. 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.
1) Engine (additional specs., see Section F – Engine Build Sheets)
a) Full preparation cars only:
1. 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.
2. 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.
3. All air entering the intake tract shall pass through the carburetor air inlet.
4. 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.
5. Filter element material is unrestricted.
6. 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:
1. 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.
2. Non-OEM Cold air induction systems are prohibited unless indicated on specification line.
3. Air filter element material is unrestricted.
4. Restrictor plates may be required. Refer to vehicle specification line.
2. Fuel Pumps/Lines:
1. 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.
2. 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.
3. Fuel Delivery:
a. Full preparation cars only:
1. 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.
2. 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:
1.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.
2.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.
4. Exhaust emission control:
1.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.
2.Catalytic converter(s) may be removed.
5.Exhaust:
a. Full preparation cars only:
1.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.
2.Exhaust after the manifolds/headers must meet the below requirements but is otherwise unrestricted.
3.No exhaust pipe(s) shall pass over the engine, bellhousing, or transmission.
4.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:
1.OEM exhaust manifolds must be maintained unless indicated on a specification line.
2.Oxygen sensors may be removed and plugged.
3.Exhaust after the manifolds must meet the below requirements but is otherwise unrestricted.
4.No exhaust pipe(s) shall pass over the engine, bellhousing, or transmission.
5.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.
6.Ignition System:
a. Full preparation cars only:
1.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.
2.Crank fire ignition systems are prohibited.
3.Any spark plugs, single coil, and ignition wires may be used.
4.Ignition timing is unrestricted.
b. Restricted preparation cars only:
1.OEM or factory equivalent ignition system must be utilized for detection and distribution.
2.OEM or factory equivalent coils must be utilized.
3.Any spark plugs and ignition wires may be used.
4.Ignition timing is unrestricted.
7. Battery:
1.Any 12-volt battery may be used.
2.The battery may be relocated as per GCR section 9.3 Batteries.
3.Additional battery hold down devices may be used and are strongly recommended.
8. Camshaft/Valvetrain:
a. Full preparation cars only:
1.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.
2.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.
3.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.
4.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.
5.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.
6.Pushrods may be replaced with any pushrods of steel (ferrous) material.
7.Valve covers are unrestricted.
b. Restricted preparation cars only:
1. OEM camshaft and valvetrain components must be utilized based on vehicle year and model.
Updating and/ or backdating within a specification line is permitted.
2. All camshaft/valvetrain hardware shall be installed/timed in conformance with those specifications
and procedures outlined by the vehicle’s manufacturer.
3. Alternate camshafts may be specified for performance equity. See specification line.
4. Valve covers are unrestricted.
9. Oiling system:
1. Oil pans, pan baffles, scrapers, and windage trays, oil pickups, lines, and filters are unrestricted.
2. A pressure accumulator/” Accusump” may be fitted.
3. The location of the filter and accumulator are unrestricted, but they shall be securely mounted
within the bodywork.
4. All oil lines that pass into or through the driver/passenger compartment shall be metal or metal
braided hose.
5. Engine oil and oil additives are unrestricted.
6. 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.
10. Accessory Drive:
a. Full preparation cars only:
2. Engine drive belts and pulleys may be replaced with any non-tooth driven belt and appropriate
pulleys for the purpose of component RPM reduction.
3. Any mechanical (non-electrical) water pump may be used provided it is mounted in the original
position.
4. 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.
5. Any power steering and/or alternator brackets may be used if they perform the same mounting
function as the originals.
6. Air conditioning systems may be removed in whole or in part.
b. Restricted preparation cars only:
7. Engine drive belts and pulleys may be replaced with any non-tooth driven belt and appropriate pulleys
for the purpose of component RPM reduction.
8. OEM or factory equivalent alternator, power steering pump and water pump may be used for repair
purposes.
9. Air conditioning systems may be removed in whole or in part.
11. Engine Components:
(a) Full preparation cars only:
6. Engine block shall be cast iron as produced by the vehicle’s manufacturer and must meet the
requirements in Section F – Engine Build Sheets.
7. Main cap girdles may be fitted.
8. Any aluminum replacement piston with three piston rings may be used. See Section F –Engine
Build Sheets for additional specifications.
9. Piston rings are unrestricted.
10. Balancing and “blueprinting” of the engine assembly are permitted. Lightening of parts beyond the
minimum material removal necessary to balance is prohibited.
11. An alternate, commercially available, vibration dampener may be fitted.
12. 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.
13. 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 (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.
14. Valve guide material is unrestricted.
15. Milling of the cylinder head to increase compression ratio is permitted.
16. Any or all valve seats may be replaced. Valve seat material must be ferrous.
17. 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.
18. 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.
19. 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.
20. Aftermarket starters mounted in stock location are permitted.
21. Engine gaskets are unrestricted.
22. Motor mounts are unrestricted. Engine must remain in the original, or approved location.
(b) Restricted preparation cars only:
6. 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:
7. Pistons and rings Bearings
8. Oil pump Starter Seals Gaskets
9. 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).
10. OEM oversized piston rings or factory equivalent may be used for repair purposes.
11. OEM oversized bearings or factory equivalent may be used for repair purposes.
12. 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.
13. Balancing is allowed. Removal of material solely for the purposes of balancing is permitted.
14. Motor mounts are unrestricted. Engine must remain in the original location.
15. Maximum allowed compression ratio for all restricted preparation cars is specified in the vehicle’s
specification line.
12. Flywheel/Clutch:
(a) Full preparation cars only:
6. Any flywheel of stock diameter and weighing a minimum of 15.0 lbs. with ring gear may be used.
7. Any clutch disc and pressure plate of stock diameter may be used.
8. Pressure plate/clutch cover assembly shall be ferrous only and shall bolt in the original stock
mounting location.
9. Balancing of the flywheel/clutch cover assembly/pressure plate is permitted.
10. SFI 1.1 or 1.2 spec flywheel and clutch are allowed,they must meet the above specifications. Method
of clutch actuation is unrestricted.
(b) Restricted preparation cars only:
6. OEM or factory equivalent flywheel, clutch disc, pressure plate, and throwout bearing must be
utilized.
7. OEM method of clutch actuation must be maintained. i.e., hydraulic, or mechanical with
concentric or lever style throwout bearing.
13. Misc. Engine Components:
1. All engine components not otherwise listed in these rules shall meet factory specifications for stock
parts.
14. Cleaning:
1. 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.
15. Coatings/Paint:
1. 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.
16. Engine Cooling System:
(i) Radiator:
1. Any radiator may be used, provided it can be mounted in the original location and requires no body or
chassis modifications to install.
2. Catch and/or expansion tanks may be added or substituted.
3. Engine coolant fluid is unrestricted.
4. Coolant/heater hoses and clamps may be substituted. Heater hoses may be plugged. Heater water
control valve(s) may be added or substituted.
5. 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.
6. Thermostats may be modified, removed, or replaced with blanking sleeves or restrictors.
7. Screens may be mounted in front of the radiator and/or oil cooler(s) and must be contained within the
bodywork.
17. Coolers:
1. Engine and power steering oil cooler(s) may be added or substituted.
2. Location within the chassis is free, provided that it/they are not mounted within the
driver/passenger compartment.
18. Cooling
(i) Fans:
1. Any cooling fans may be used. Cooling fans may be removed.
2. Electrically operated fans with manual or automatic actuation may be fitted.
19. Transmission/Final Drive:
(a) Transmission: Full preparation cars only:
1. 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.
2. Any conventional H-pattern, non-sequential shifter may be used.
3. Transmission mounts are unrestricted.
4. Transmission lubricants are unrestricted.
5. Transmission coolers are permitted. Dry Sump transmission coolers are not permitted.
(b) Transmission: Restricted preparation cars only:
1. OEM or Factory equivalent transmission components must be utilized. Updating and/or backdating
within a specification line is permitted.
2. Transmission repair procedures may be performed utilizing OEM procedures.
3. Any conventional H-pattern, non-sequential shifter may be used.
4. Transmission mounts are unrestricted.
5. Transmission lubricants are unrestricted.
6. Transmission coolers are permitted. Dry Sump transmission coolers are not permitted.
20. Driveshaft:
(a) Full preparation cars only:
1. OEM driveshafts may be replaced with any one-piece driveshaft of steel or aluminum
construction.
2. The driveshaft may be modified to fit alternate differentials and/or transmissions.
3. Driveshaft loops are permitted/recommended.
(a) Restricted preparation cars only:
1. OEM driveshafts may be replaced with any one-piece driveshaft of steel or aluminum
construction.
2. Driveshaft loops are permitted/recommended.
21. Rear Axle/Final Drive:
(a) Full preparation cars only:
1. Any OEM rear axle assembly is permitted, provided it was available in the listed vehicles
contained within the specification line.
2. Ford 9” rear axles are permitted in all cars. Center section shall be of ferrous material.
3. Dana 44 axles are permitted in all cars.
4. Any final drive ratio is permitted.
5. Any limited slip or locked differential is permitted.
6. C-clip eliminators are permitted.
7. Full floater axles are permitted.
8. Aftermarket or modified rear differential covers are allowed.
9. Differential coolers are permitted. Dry Sump differential coolers are not permitted.
10. For any rear axle assembly, welding of the rear axle tubes is permitted.
(b) Restricted preparation cars only:
1. Any OEM rear axle is permitted, provided it was available in the listed vehicles contained within
the specification line.
2. Any final drive ratio is permitted, provided it fits the allowed stock differential housing without
modification to the housing.
3. Any limited slip or locked differential is permitted.
4. Aftermarket or modified rear differential covers are allowed.
5. Aftermarket axle shafts and bearings are allowed.
6. Differential coolers are permitted. Dry Sump differential coolers are not permitted.
7. C-clip eliminators are permitted.
8. For any rear axle assembly, welding of the rear axle tubes is permitted.
22. 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 maybe 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 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:
(a) 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 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 arm on GM F-body cars and the upper arm on Ford Mustangs is 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.
23. Brake System:
i. Materials:
1. Brake pads, brake linings, and brake fluid are unrestricted.
2. 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.
3. Hubs shall be of ferrous material or aluminum.
4. Rotor hat shall be of ferrous material or aluminum and may be part of the hub or rotor.
5. 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.
6. Mounting brackets shall be of metallic material.
7. Materials may differ from above if OEM hardware is utilized.
8. Brake duct fans are permitted for cooling brakes. They shall perform no other function.
ii. Components: Full preparation cars only:
1. 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.
2. Parking brakes, mechanisms, and actuating components may be removed.
3. One piece front or rear hub with rotor may be replaced with separate hub, rotor hat, and
rotor.
4. Front spindles/knuckles may be modified to facilitate mounting of alternate brake calipers.
Spindle modifications shall serve no other purpose.
5. Any front caliper using four (4) or fewer pistons and using one (1) brake line per caliper is
allowed.
6. Any rear caliper using four or fewer pistons and using one brake line per caliper is allowed.
7. Rear caliper mounting brackets may be substituted
iii. Components: Restricted preparation cars only:
1. 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.
2. 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.
3. 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)
iv. System Control:
1. Brake system circuitry may be revised.
2. The original master cylinder may be replaced with any single or dual master cylinder (with
balance bar).
3. 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.
4. Any brake booster may be used. The brake booster may be removed. A vacuum reservoir or
booster may be added
5. A brake-bias adjustment cable is permitted.
6. Brake proportioning valves may be used provided that they are of the inline, pressure limiting
type.
7. ABS and traction systems must be disabled. It is the responsibility of the competitor to provide
proof of system disabling.
24) Wheels/Tires:
(i) Wheels:
1. Maximum wheel diameter is 17 inches, unless otherwise indicated within the vehicle specification
line.
2. 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.
3. Knockoff or quick-change type wheels are prohibited.
4. 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.
5. 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.
6. Any wheel stud, bolt, and/or nut is permitted.
(ii) Tires:
1. Max tire size for all cars is 275, unless indicated within the vehicle specification line.
2. Weight penalty for increased width may be assigned within specification line.
3. Tires must conform to GCR section 9.3 Tires.
4. American Sedans must compete on DOT “R-type” road race tires. Permitted tires are listed below.
Soft “A type” autocross tires are prohibited:
5. 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, A052, ADVAN or AO55 Maxxis RC-1
6. 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.
7. 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.
8. Additional tires may be requested for consideration by the ASAC and may be introduced within
rule change timing cadence.
24) Body/Structure:
(i) Fenders:
1. Fenders and wheel openings shall remain unmodified.
2. It is permitted to roll under or flatten any interior lip on the wheel opening for tire clearance.
3. 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.
4. Any non-metallic inner fender liners may be used or removed.
(ii) Air Dams/Spoilers:
1. A front spoiler/air dam is permitted.
2. The front spoiler/air dam shall not protrude beyond the overall outline of the body when viewed
from above perpendicular to the ground.
3. The front spoiler/air dam shall be mounted to the body, and shall extend no higher than four 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.
4. The front spoiler/air dam shall not extend toward the rear of the car further than the vertical
centerline of the front wheel hubs.
5. The front spoiler/air dam shall not cover the normal grille opening(s) at the front of the car.
6. Openings in the front spoiler/air dam are permitted for the purposes of ducting air to the brakes,
cooler, and radiator.
7. Rear spoilers or wings shall be as originally fitted or as specifically authorized on the specification
line for that vehicle.
(iii) Bumpers/Fascia:
1. 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.
2. Front parking/fog light assemblies may be removed for ducting of air.
(iv) Hood/Roof/Trunk/Rear Deck:
1. Hood and trunk pins, clips, or positive action external latches are permitted.
2. Stock hood and trunk latches may be disabled or removed; if so, some positive action external fastening
method shall be used.
3. Any hood/trunk hinges may be used. Hood/trunk hinges may be removed.
4. Under hood bracing on stock hoods, trunks, and rear decks may be modified or removed.
5. 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.
6. Ram air openings and rear openings must be blocked off to prevent passage of air.
7. 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.
(v) Glass:
1. OEM or factory equivalent windshield is required.
2. 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.
3. Polycarbonate windows must retain the same shape, size and location as OEM and must be
securely fastened to the car.
4. 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.
5. Windshield defrosters are allowed as long as they serve no other purpose.
6. Any windshield wipers, motors, arms, and brackets maybe used or removed.
(vi) Doors:
1. 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.
2. 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.
(vii) Frame/Subframe:
1. The frame or subframe shall be stock for body used.
2. 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”.
3. 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.
4. A connector may be added between the left and right front frame rails forward of the front axle centerline.
(viii) Weather Stripping/Seals:
1. Engine compartment, trunk, hatch, and door rubber seals or weatherstripping may be removed.
(ix) Repair/Modification:
1. All chassis/structural repair, if performed, shall be in concurrence with factory procedures,
specifications, and dimensions.
2. 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.
3. 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.
4. 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.
5. All exterior and interior trim, grills, moldings, vents, badges, and screens may be removed.
Resulting holes may be covered.
25. Driver/Passenger Compartment:
(i) Interior:
1. All seats and seat brackets may be removed.
2. 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.
3. 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.
4. Any steering wheel except wood rimmed types may be used.
5. Any gear shift knob may be used.
6. Gauges and instruments are unrestricted. Any instrument panel may be used.
7. Any interior or exterior mirrors may be used.
8. Sunvisors, seat belts and their attaching hardware and bracketry may be removed.
9. Complete removal of interior panels is allowed in all or part.
10. Any removable covers used to cover spare tires, tools, bins, etc., may be removed along with
attaching hardware and bracketry.
11. Carpets, mats, and their insulating or attaching materials may be removed from the floor and recesses
of the cargo/ trunk/spare tire area.
12. 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.
26. Safety:
(i) Restraint Systems:
1. Airbags/passive restraint systems shall be removed.
(ii) Headlights:
1. Headlight and headlight operating ancillaries may be removed.
2. 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.
3. 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.
(iii) Steering Column:
1. The steering column is unrestricted.
2. A collapsible type steering column is strongly recommended.
3. The driver’s normal seated position must not be relocated.
4. Full Preparation cars that have OEM electric steering may remove it.
(iv) Roll Cage:
1. 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.
26. Miscellaneous:
(i) Hardware/Fasteners:
1. Hardware items (nuts, bolts, etc.) may be replaced by similar items performing the same
fastening function(s).
(ii) 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.
5. 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.
6. ENGINE BUILD SHEETS (Full Preparation only)
(a) Full Preparation (Full prep Verbiage)
1. Crate Motor equipped full preparation vehicles.
2. The following “Crate motors” may be utilized in Full preparation vehicles:
3. Ford Performance M-6007-D347SR7 engine assembly for Ford produced vehicles.
4. GM Performance parts CT400 P/N-1937 → 0604 or 1937 → 0604 engine assembly for GM produced
vehicles.
5. 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:
a. Oil pan and oil pump pickup.
b. Valve/Rocker covers.
c. Distributor assembly
d. Spark plugs
e. Water pump
f. Thermostat
g. Fuel pump
6. Disassembly of the engine is permitted for repair. All components must be replaced with exact OEM replacement
components.
7. “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.
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.
BLOCK
Crankshaft Housing Bore: 2.4412-2.6416” Block Deck Height:
GM: GM: 8.9970”-9.0430”
Ford: 8.1880-8.2240”
Bore Spacing:
GM: 4.4000”
Ford: 4.3800”
Roller bearings of any type are not permitted for the camshaft, rod, or crankshaft bearings.
Options:
• One-piece rear main seal adapter (with seal) may be used.
• Cylinder block oil restrictors may be installed.
• Block may be machined for the purpose of installing cylinder O-rings.
• Block may be machined to true warped surfaces.
• Block casting seam flash may be deburred.
• Lifter bore sleeving is permitted.
• A maximum of two cylinders may be sleeved.
• 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.
• GM vehicles – Dart P/N SHP3116 → 1111 or World Product 084010
• Ford vehicles – Dart P/N SHP3137 → 4175 or World Product 087110
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.
2.
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.
CRANKSHAFT
Main Journal Dia (Min): 2.2182”
Rod Journal Dia (Min): 2.0690”
Options:
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.
Crankshaft casting seam flash may be deburred.
PISTON
Material: Aluminum (Cast or Forged)
Ring Configuration: 3 rings, above pin
Dome Configuration: Any dome configuration is permitted.
Pin Diameter: .930” Max
Options:
Pins may be centered or offset. Offset shall not exceed factory specifications.
CYLINDER HEADS
Edelbrock (Ford and Chevy)
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
Options:
Flo Tek (Chevy #102-500)
Valve Job (Head): Refer to Figure 1 Intake Valve Size (Max): 2.02” Exhaust Valve Size (Max): 1.6” Port Volume (Max.):
see spec line
Options:
Flo Tek (Ford #203-500)
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
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.
Note:
1. Absolutely no modification, machining, tooling, etc. of the combustion chambers is permitted.
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.
MEASUREMENT STANDARDS
Measurement standards shall be as specified in Appendix G. with the following exceptions: Wheelbase has a tolerance of