ATK Engines HP32 Chevy 350 Base Engine, 350HP, 1 Pc. Rear Main

ATK's HP32 is a 350CI Chevy long block built on a seasoned OE roller block with a 4 bolt main and 1pc seal, rated at 350 HP and 400 lb-ft (TQ) of torque. ATK describes the idle as noticeable while still holding good vacuum for your power accessories.

Inside the engine

The 4.040" x 3.480" bore and stroke pairs an OE reground crankshaft, externally balanced at the rear and internally at the front, with OE powder metal 5.7" rods and hypereutectic 9.5:1 compression pistons. A hydraulic roller cam specs out at 220/224 @.050 duration with .495in/.502ex lift on a 110LSA, feeding Vortec cast iron heads with 67cc chambers and 1.94/1.50 valves through 1.5 ratio stamped steel rocker arms.

What to check before buying

The included rear sump 5qt oil pan does not fit every chassis: ATK excludes Chevelles with steering behind the crossmember, some Corvettes, and early Chevy II applications, so confirm oil pan clearance for your chassis before ordering. ATK builds this as an engine-change part rather than a direct OEM replacement, and buyers in California need separate approval through the state's Bureau of Automotive Repairs.

Common questions

What's the horsepower and torque rating? 350 HP and 400 lb-ft of torque.

Will the oil pan fit my car? Not in every case; ATK excludes certain Chevelle, Corvette, and Chevy II applications from the included rear sump pan.