ATK HP55C GM 383 Stroker 500HP Stage 3 Complete Crate Engine

Description

Power competitive weekend bracket dragsters using the ATK HP55C Crate Engine in Stage 3 complete trim. Pumping out 500 horsepower at 6,000 RPM and 475 lb-ft torque at 4,600 RPM, this 383 cubic inch Chevrolet stroker arrives dressed with carburetor, ignition, and water pump. It provides turnkey high-RPM performance straight from the pallet for serious street-strip competitors.

A precision-machined 4-bolt main cast iron GM block forms the rigid backbone with finish-honed cylinder walls. Inside resides an electronically balanced rotating group: a 4340 forged steel 3.800-inch crankshaft, 4340 forged 5.700-inch H-beam rods, and 10.5:1 forged pistons across a 4.000-inch bore. Oil stays secure inside an external-balance 5-quart passenger-side dipstick steel pan with internal oil splash baffles.

Key Features of ATK HP55C

Drag racers choose to buy ATK HP55C crate engine packages to eliminate parts procurement headaches during high-performance vehicle transformations. The turn-key configuration fits vintage Chevrolet Chevelles, bracket Novas, and custom street rods with ease.

• 750 CFM mechanical secondary carburetor comes pre-calibrated to ensure crisp throttle response and clean high-RPM fuel flow.
• Single-plane aluminum intake manifold maximizes cylinder charge velocity across an aggressive 3,000 to 6,200 RPM powerband.
• HEI ignition distributor provides a simple one-wire hookup with an internal coil for reliable high-voltage spark delivery.
• 64cc aluminum heads optimize combustion flame travel while pulling excess heat away from exhaust valve seats.
• 195cc intake ports provide exceptional airflow velocities that elevate cylinder filling efficiency past 5,500 RPM.
• 0.555-inch lift hydraulic roller camshaft minimizes internal friction while producing an aggressive, hard-hitting exhaust note.
• ATK HP55C complete assemblies include a high-flow water pump, performance spark plug wires, and chrome dress accessories.
• 1.5:1 ratio roller rockers guide the valves accurately without valve stem galling during hard acceleration runs.

Dyno Output Fuel Requirements

Dynamometer validation certifies 500 horsepower at 6,000 RPM and 475 lb-ft torque at 4,600 RPM. The engine pulls without hesitation across an operating envelope of 3,000 to 6,200 RPM. Designed for 93-octane premium pump gasoline, it creates 12 in-Hg manifold vacuum at 850 RPM idle. Operating oil pressure ranges safely between 45 and 65 PSI hot.

Crossmember Clearances Drivetrain Coupling

Built on traditional small-block dimensions, the package clears front suspension crossmembers in GM muscle cars without modification. The crank tail requires an external-balance flexplate or flywheel to bolt straight to common GM automatics or manual transmissions. Factory motor mount positions eliminate clearance headaches around full-length exhaust headers and manual steering linkages.

Break-In Instructions Usage Parameters

Prime the engine using a mechanical shaft tool through the distributor hole to protect internal surfaces before turning the starter. Use 10W-30 break-in oil rich in ZDDP zinc additives to lubricate internal bearing shells. This turn-key engine is not engineered for marine closed-compartment use, boost surpassing 6 PSI, or continuous alcohol fuel operation.

• Discard break-in engine oil and install a high-efficiency filter canister after the first 500 road miles.
• Inspect carburetor throttle linkage, fuel line fittings, and baseplate bolts every 3,000 miles of street use.
• Check ignition distributor advance weights, rotor contacts, and spark wires every 12 months or 12,000 miles.

Factory Guarantee Crate Contents

ATK protects your investment with a 24-Month or 50,000-Mile factory warranty against defects in components or machining. The wooden crate contains the complete engine, carburetor, intake manifold, distributor, plug wires, water pump, balancer, flexplate, and dyno record sheet.