ATK HP98C Chevy 350 Complete Engine 345HP

Intake, carburetor, distributor, and fuel pump already bolted on separate the HP98C from ATK's bare 350 long block, while output holds at 345 horsepower with 400 foot-pounds of torque.

What ships installed

An ATK dual-plane intake feeds a Quick Fuel 680 CFM carburetor with vacuum secondaries and an electric choke, fired by an HEI distributor and fed by a mechanical fuel pump. The oil pan, timing cover, water pump, harmonic balancer, and flexplate all ship in place, so this build sits closer to ready-to-run than ATK's bare long block.

Inside the long block

The same 4.040-inch bore and 3.480-inch stroke as ATK's other 350 long blocks give this engine its displacement. Stamped-steel 1.5-ratio rockers work the ATK cast iron heads, over hypereutectic pistons set at 9.1:1 compression, driven by a double roller chain. ATK specifies conventional 10W30 oil carrying a zinc additive across the first 3,000 miles of operation, followed by 91 octane fuel.

Q: Does it include a flexplate? Yes, the flexplate ships installed along with the harmonic balancer and water pump on this complete build.

Choosing the complete version over the bare long block saves a trip to source an intake, carburetor, distributor, and fuel pump separately, which matters most for a swap where you want the engine close to ready to fire with minimal extra shopping beforehand.