UNLTD Off-Road Racing, Organizers of the Mint 400, Parker 400, and California 300 off-road races, has updated its rulebook and now requires Chevrolet’s 6.2L engine for the Unlimited SPEC Truck Class.
Drivers who compete in the Unlimited SPEC Class for the Mint 400, Parker 400 and California 300 will have to run a new spec engine starting in 2024. UNLTD Off-Road Racing has partnered with Chevrolet Performance to standardize the spec engine for the unlimited class around the well-known 6.2L V8. The engine will be race spec, factory sealed, and available from local Chevrolet Dealerships.
The Unlimted Spec Class (Numbers 200-299) runs “Unlimited” suspension and chassis configurations but with a “SPEC” or specified engine. Starting during the 2024 Mint 400, that specified engine will be the 525RLB Chevrolet V8, Part Number 19435005.
The 525RLB is functionally identical to a 6.2L V8 that you’d find in a Silverado or Sierra, but comes as a sealed and ready-to-race long-block. It’s rated at 533 horsepower and 477 lb-ft of torque with a four-barrel carburetor. It requires an induction system, ignition control system, starter, fuel system, exhaust, and accessory drive system. It has a 6-quart racing oil pan and is specifically designed for universal sanctioning bodies. It also comes with factory-installed anti-tampering seals. Maybe it goes without saying, but the 525RLB is not intended for street use.
2024 ULTD Off-Road Racing Unlimited SPEC Class Engine Rules
- Engine must be GM 525RLB part #19435005. Engine is a factory sealed engine and all seals must remain untampered with as delivered by the manufacturer.
- Intake manifold must be GM part# 12686561 and must remain stock as delivered by the manufacturer.
- Throttle Body must be GM part #19420701 must remain stock as delivered by the manufacturer.
- Fuel rail open.
- Fuel Injectors are restricted to GM part #12576341
- Power steering pump and alternator are open. Oil pan may be modified for fit, but must be removed and reinstalled and resealed by an Unlimited Off-Road Racing approved engine sealer.
- No dry sump. Pulleys and belts are open. Must use a stock production ECU. ECU may be reflashed.
- Engines can only be repaired or rebuilt by an approved engine rebuilder. Racers may choose to have an approved engine builder rebuild their engine to stock standards or buy an entirely new engine. If it’s a partial rebuild, Chevrolet will provide parts to the approved engine rebuilder to rebuild the engine back to stock.