ATK HP31 Chevy 350 87-95 TBI Base Engine 290HP

The ATK HP31 is a Chevy 350 base engine built to drop into 87-95 TBI trucks, rated at 290 hp and 373 lb-ft of torque on a mild hydraulic roller cam matched to factory throttle-body injection rather than a carburetor.

Who this engine suits

This engine is meant to run with your vehicle's existing stock components, but ATK is clear that the ECM needs a performance chip burned for it to run correctly, and an upgraded intake and headers are called for to get the most from it. OE-style TBI heads open to 1.94/1.50 at the factory 350 bore and stroke.

What to check before you buy

• This block is specifically for 87-95 Chevy trucks running the factory 350 TBI setup, not a general-purpose 350 swap.
• A performance chip burn for the ECM is required; running it on the stock chip is not expected to work correctly.
• Lubrication relies on a Melling pump at standard volume, nothing exotic for this mild combination.

Common questions

Will it run on the stock computer? Not as shipped; the ECM needs a performance chip burned first.

Does it include the TBI intake? No, intake, spark plug wires, and water pump are ATK's recommended parts, not installed.

What year trucks is it for? 1987 through 1995 Chevy trucks running the factory 350 TBI setup. California requires BAR compliance for engine swap installations.