ATK Engines HP94-TBI Chevy 383 Custom TBI Cam, 415 HP

The ATK HP94-TBI shares its 415 hp, 460 lb-ft bottom end with ATK's carbureted 383 stroker, but the camshaft is ground specifically for a throttle-body-injection setup rather than a carburetor, which is the detail that separates this listing from the rest of the HP94 line. Who this engine suits The crankshaft is Scat's nodular-iron forging, matched to Scat's I-beam rods and ARP 8740 rod bolts, under hypereutectic pistons and aluminum cylinder heads. Choose this version if your plan is a factory-style or aftermarket TBI system; unlike the carbureted base engine, this one ships with its intake manifold and harmonic balancer already in place, which is one less part to source on your own. Before you order, check this Flexplate and flywheel are not included, so match those to your transmission choice before ordering. A double-roller timing chain drives the cam, with billet aluminum roller rockers at a 1.6 ratio working the valves. Plug gap and firing order follow ATK's standard sheet for the 383 platform. Common questions Will this run a carburetor instead? It is cammed for throttle-body injection, so confirm fitment with us before planning a carburetor conversion. Is the harmonic balancer included? Yes, unlike ATK's base 383 long block, the balancer ships installed here. What octane does it need? ATK calls for fuel at 91 octane or higher. California requires BAR compliance for engine swap installations.