ALL CRATE ENGINE

Part Number: 12498772

ALL  CRATE ENGINE - Part Number 12498772
Crate Engine ZZ383/425. Big block-style power in a small-block package. Highlights: HP: 425 @5400 rpm TQ: 449 @4500 rpm Late-style block with one-piece rear main seal Four bolt main caps Forged steel crankshaft Hydraulic roller camshaft Forged PM rods Aluminum Fast Burn cylinder heads P/N 12464298 with center-bolt valve covers Hydraulic roller camshaft 9.1:1 compression ratio In almost any other scenario, an engine producing 425 horses and 449 neck-tugging lb. ft.of torque would have the words "big" and "block" in the description. Not this one. The ZZ383/425 is a stroker small-block with the strength of its Mark IV cousins. 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 stats. 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 recipe, for great mid- and high- rpm power which, when combined with the 383 displacement, creates a fantastic all-around performer. The ZZ383 has a specially modified engine block and 3.80-inch-stroke crankshaft which enable its 383 cubic inches of displacement. 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 - to ensure bulletproof performance. With the ZZ383/425 you get the power of a big-block with the size and weight of an aluminum-head small-block. It's one of the rare combos that lets you eat your cake and beat the pants off the next guy, too. Installation Notes: Requires addition of carburetor, ignition, 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 inch automatic transmission flexplate. Requires 1986-1999 350 style externally balanced flywheel for manual transmission. Intended for 1979-and-earlier pre-emissions street vehicles and all off-road vehicles.
ZZ383/425

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