ATK GM 496 Stroker 600 HP HP631PM Stage 2 Big Block

Description

Connecting rod failure and heat fatigue sideline high-load transport trucks during peak operating seasons. The ATK GM 496 Stroker 600 HP HP631PM Stage 2 Big Block provides reliable pulling reserve through an industrial engine rebuild. This 8.1L 8-Cylinder stroker delivers 600HP, though installers must ensure proper exhaust header tube clearance around the enlarged oil pan kickouts.

Poured using ASTM A48 Class 35 heavy iron, this ATK engine core pairs with high-port A356-T6 aluminum heads and a 4340 forged steel crank. Cold starter draw pulls 190A on 12V circuits. Bare engine weight reaches 545 lbs across 31in length, 28in width, 29in height dimensions with 6.0 quarts oil capacity.

Key Features of ATK HP631PM

Fleet operators buy ATK GM 496 Stroker 600 HP HP631PM Stage 2 Big Block units to bypass tedious component sourcing while retaining their preferred fuel induction systems. The mid-dress configuration delivers a pre-torqued intake manifold and high-flow water pump mounted directly to the engine block.

• Stroker 496ci displacement pairs a 4.310in bore with a 4.250in stroke for immense torque reserve.
• Mid-dress components include the dual-plane high-rise intake manifold and high-flow water pump.
• Lightweight aluminum cylinder heads vent combustion heat rapidly to prevent detonation under load.
• AISI 4340 forged steel H-beam rods resist catastrophic deformation under sudden deceleration loads.
• HP631PM commercial core tolerances ensure continuous bearing oil film retention at high temperatures.
• Four-bolt main bearing caps prevent crankcase distortion during severe torque converter stall.
• Hardened steel pushrods maintain straightness under heavy valvetrain spring seat pressures.

Shop Dynamometer Load Tolerances

Dyno testing validates performance on each HP631PM long block engine before dispatch. Output reaches 600HP at 5500 RPM and 610 ft-lbs torque at 4200 RPM under continuous testing. Oil gallery operating pressure indicates 60 PSI at 195°F oil temperature. Cylinder compression averages 190 PSI per bank within 3% variance. Crank journal runout checks out at 0.0003in TIR. Steady exhaust gas temp settles at 1320°F at full load.

Chassis Installation Service Tasks

Throttle return linkage pull measures 6 lbs force. This high-performance big block is NOT suited for factory low-stall stock converters, direct-injection computer systems, or low-octane standard pump fuels.

• Flush break-in engine oil and replace the filter element after 500 highway transit miles.
• Set hydraulic lifter preload to one-half turn down past zero lash when cold.
• Check water pump mounting bolt torque at 30 ft-lbs following initial temperature cycles.

Commercial Warranty Shipping Crate

Adhering to the rigorous ATK assembly standard, this heavy-duty unit carries a 2-Year 24,000-mile commercial warranty. Each shipping crate contains the mid-dressed engine, intake manifold, water pump, valve covers, oil pan with pickup, and an official dyno verification sheet.