ATK HP107C Chevy 383 Stroker Complete Engine 525HP

ATK's HP107C is the fully dressed version of its top 383 stroker build, carrying the same 525 hp, 515 lb-ft combination as the base HP107: a Scat 4340 forged crank and H-beam rods under 10.2:1 forged pistons, with the largest cam ATK uses in this stroker line.

What this tier adds

Those same Dart aluminum heads reappear here, a 70cc chamber and valves set at 2.02/1.60. Where the base long block leaves the intake, distributor, water pump, and balancer for the installer, this complete version has them bolted on and ready to fire.

Things to confirm before ordering

• Induction is a single-plane setup, not a dual-plane, so low-speed vacuum signal is weaker than on ATK's milder street engines.
• Flexplate and flywheel still depend on your transmission choice, and neither ships either way.
• Confirm which ignition parts ship physically mounted with us before ordering.

Common questions

What's different from the base HP107? This version has the intake, distributor, water pump, and balancer installed instead of left for the builder.

Will it work with power-brake vacuum? Single-plane induction like this is not built for strong vacuum signal, so plan accordingly.

Is a flywheel included? No, flexplate or flywheel choice is left to match your transmission.

Is this the same block as the base HP107? Yes, the Scat crank, H-beam rods, and forged pistons are unchanged; only the installed hardware differs. California requires BAR compliance for engine swap installations.