Tech Specs: Inside Chevy’s 91°µÍø Pro Stock engine—The 500-cid DRCE
Tracing its roots to the Chevy Mark IV Rat Motor, the Chevrolet Performance Drag Racing Competition Engine (DRCE) delivers more than 1,400 electronically fuel-injected horsepower to a pair of Goodyears for a 6-second ride down the quarter-mile in an excess of 200 mph. Today, the engine can be found in Chevy, Dodge, Ford, and Pontiac Pro Stock cars and may be the most refined engine to ever grace a National Hot Rod Association dragstrip.
91°µÍø Pro Stock Engine
Performance: More than 1,400 hp and 800 lb-ft of torque
Engine speed limit: 10,500 rpm
Engine Block
Design: 90-degree V-8, with four-bolt steel bearing caps (center three caps are splayed), based on Mark IV big-block Chevy design Material: Cast iron (DRCE 2); cast iron or compacted-graphite iron(CGI) (DRCE 3 and DRCE 4)
Maximum displacement: 500 cid
Bore: 4.700 inches
Stroke: 3.600 inches
Bore center spacing: 4.900 inches
Cam-to-crank centerline: 5.750 to 7.067 inches
Cost: $4,700 (DRCE 2); $8,000 (DRCE 3 CGI); n/a (DRCE 4 CGI)
Crankshaft
Material: CNC-machined steel, based on big-block Chevy
Oiling system: Dry-sump
Fuel System
Type: Electronic multi-port Holley fuel injection
Throttle body: 25-square-inch Holley unit required on all engines
Fuel: Sunoco SR18 (118 octane) gasoline
Fuel pump: Engine driven or electric, 90 psi maximum pressure
Injectors: 80 or 160 pound per hour Holley units, maximum of eight
Fuel burned per run: 1 gallon
Intake Manifold
Material: billet aluminum
Ignition System
Type: Coil-near plug Holley crank-trigger system with eight sparkplugs
Cylinder Heads
Material: Cast T355-T7M aluminum
Number of valves per cylinder: Two
Intake valve diameter: 2.55 inches (approximately)
Exhaust valve diameter: 1.80 inches (approximately)
Valve covers: Fabricated aluminum
Valvetrain
Camshaft: Roller-lifter style
Camshaft diameter: 70 mm
Typical lift: 1.10 inch
Lobe separation: 116 degrees
Duration: 280 degrees (intake); 308 degrees (exhaust)
Rocker-arm ratio: 1.75:1 to 2.00:1
Exhaust system: Four-into-one or tri-Y headers
Want to see how a 70mm DRCE camshaft compares to a big-block Chevy? Watch this.