Addition of a limited prep LS Chevy engine for GT1
#37045 from Robert Logsdon · Rule change · TB 25-01 (2025-01 Fastrack)
In GCR, Section 9.1.2. GT1 Spec Lines, GT1 Approved Automobile List, LS1 V8 engine allowed with stock intake, add the
following:
"LS1 Limited Prep GT1 motor
2600 # with driver
Blocks : GM castings or aftermarket, no lightening, Max volume 383 cubic inches
Cylinder Heads: GM LS castings or aftermarket, stock valve angle, intake and exhaust ports must be in stock location, porting
and polishing allowed
Valves: No titanium valves, must be stock size for head part number
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Rockers: Factory 1.7 rockers only, aftermarket trunion mod allowed
Pushrods: Free
Intake manifold: stock EFI for variant used or GM 525 carb intake or Edelbrock carb variants ie: Performer RPM, Victor, Victor Jr.
or similar.
Camshaft: Hydraulic roller only, standard journal size, lift and duration free
Timing chain: single or double roller type only
water pump: stock or aftermarket in stock location
Harmonic dampener: SFI approved,
Pistons: Factory or aftermarket flat top pistons only, valve reliefs allowed, coatings allowed
Crankshaft: Factory or forged steel aftermarket, 50 lb min. weight
Rods: GM stock or aftermarket forged steel
Carburetor: one 4150 type 750 cfm max"