ATK HP107 Chevy 383 Stroker Base Engine 525HP

The ATK HP107 tops ATK's 383 stroker base-engine lineup at 525 hp and 515 lb-ft of torque, running a Scat 4340 forged crankshaft and matching Scat H-beam rods under forged pistons at 10.2:1 compression, with the largest cam used across ATK's stroker line.

Who this engine suits

Dart's aluminum heads use a 70cc chamber with 2.02/1.60 valve sizing. A 7-quart Moroso oil pan with a windage tray handles the oiling side, since higher-RPM use calls for more pan capacity than ATK's milder 383 builds carry. This is a base long block, so the single-plane intake, mechanical-secondary carburetor, distributor, and water pump are not mounted; ATK lists them only as suggested parts for a builder assembling a street-strip top end.

A few things worth confirming

• A roller-rocker set and a double-roller timing chain finish out the valvetrain.
• Stall speed and carburetor tuning for this cam are steeper than ATK's other 383 stroker engines; ask us for the specifics before you order ignition and fuel parts.
• Premium fuel is called for at this compression ratio.

Common questions

Does it include an intake and carburetor? No, induction parts are suggestions on this base long block, not installed hardware.

What oil pan is used? A 7-quart Moroso pan with a windage tray.

What's the compression ratio? This 383 stroker runs 10.2:1, the highest in ATK's base-engine lineup.