About the ZZ572 / 620 Crate Engine

The ZZ572/620 is filled with a forged 4340 steel crank with a 4.375 inch stroke; shot peened, forged 4340 H-beam rods, and forged aluminum pistons with full floating wrist pins. A new GM single plane intake manifold and 850 CFM Demon carburetor deliver enough air and fuel to reach 620 horsepower at 5500 RPM, and 650 ft. lb. of torque at 4500 RPM. And, because of the redesigned rectangular port aluminum cylinder heads, all of this power and performance is delivered with a gas pump friendly 9.6 to 1 compression ratio.