ZZ383 - Big-block-style power from a small-block engine!

If you’re looking for a small-block Chevy that makes big-block power, we’ve got the engine for you! For the ultimate GM Performance Parts small-block crate engine, choose the ZZ383—a combination of Fast Burn aluminum performance heads and a 383" stroker small-block that can add up to 425 horsepower and 449 lb.-ft. of torque.

A carefully engineered balance of torque-producing bottom-end power and horsepower-inducing Fast Burn cylinder heads combine for the ZZ383/425’s stellar performance statistics. The Fast Burn heads have large 2.00"/1.55" valves and specially designed chambers that draw in lots of air and fuel, burning the mixture quickly and completely. It’s a combination that generates great mid- and high-rpm power, which, when combined with the 383 cubic inch displacement, creates an awesome all-around performer.

The ZZ383 has a specially modified engine block and 3.80"-stroke crankshaft, which produce 383 cubic inches of pure performance. The reciprocating assembly is comprised of heavy-duty components including a 4340, nitrided, and induction hardened forged crankshaft, and unique, heavy-duty powdered metal rods. It’s 425 horses of bulletproof performance.

With the ZZ383/425, you get the power of a big-block with the size and weight of an aluminum-headed small-block. If you’ve never driven a car with a stroked small-block and the top end components to support it, now is your chance!

Possible Applications

• The perfect small-block for your ‘55-57 shoebox
• An 11-second starting point for your street/strip car
• A street car that deserves big power
• A weekend race car that sees a lot of action

*Applications have not been validated. They are merely suggestions of how you might enjoy your GM Performance Parts crate engine. Some applications may affect engine warranty. See specific warranty information. Some applications may not be emission legal; check state and local ordinances.

Part #: 12498772

Installation Notes

• NOTE: Distributor with melonized steel gear MUST be used with long blocks and partial engines with steel camshafts, or engine damage will occur. We recommend HEI distributor P/N 93440806.
• Requires addition of carburetor, ignition, water intake manifold, fuel pump, water pump and starter (not included).
• 425-horsepower rating achieved during GM testing with high-rise single-plane intake manifold P/N 12496822 and a 750-cfm Demon carburetor with vacuum secondaries.
• GMPP dual-plane intake manifold P/N 12366573 may be used to avoid hood clearance problems, but peak power may decrease by approximately 15-20 horsepower.
• Comes with 12.75" automatic transmission flexplate. Requires 1986-1999 350-style externally balanced flywheel for manual transmission. See chart on page 171.
• Intended for pre-1977 street vehicles and all off-road vehicles.