Chevrolet Performance Parts 19433604 GM-Sealed 604 Crate Engine

This 604-class small-block runs on a CNC-machined cast-iron block with four-bolt main caps, topped with Fast Burn aluminum cylinder heads and LS-style beehive springs. Peak numbers land at 404 hp and 406 lb-ft, with 5,600 and 4,600 rpm marking where each one arrives. A single-plane aluminum intake manifold and a forged, shot-peened steel crankshaft anchor the combination.

Cylinder head and valvetrain details

The 62cc combustion chambers size out at 2.000 inches on the intake valve and 1.550 on the exhaust, run by a steel hydraulic roller camshaft under 1.5:1-ratio aluminum roller rocker arms; duration numbers come in at 208 degrees intake and 221 exhaust. Compression comes in at 9.72:1 nominal, and Chevrolet Performance calls for premium pump fuel with 36 degrees of total timing at 4,000 rpm, keeping revs at or below a 5,800 rpm ceiling.

What is included and what is not

Hypereutectic aluminum pistons and powdered-metal connecting rods ride inside the block, with the valve covers, oil pan, timing cover, and intake manifold already assembled onto the engine. A carburetor, distributor, throttle body, computer, and wiring harness are left for the installer to source. As with any engine-swap part, confirm current California Bureau of Automotive Repairs compliance before installing it in a vehicle registered there.

Q: What is the recommended rpm ceiling for this engine? Chevrolet Performance calls for staying at or below 5,800 rpm, with peak output arriving by 5,600.