I was looking through all the different small block Chevy crate engines from Chevrolet the other day and noticed there’s now a ZZ5. I know there have been a whole slew of different versions and obviously this is the fifth one. What makes this one different than the rest? Wasn’t the original ZZ engine rated at 345 horsepower?


Jeff Smith: The line of Chevy small block crate engines dates back to 1989 when Chevy first introduced the ZZZ small block. It employed a one-piece rear main seal, four-bolt main block with a forged crank, 9.8:1 compression hypereutectic pistons, and L98 Corvette heads. The engine also ran a somewhat long duration 235 degree at 0.050 hydraulic roller cam with 0.480-inch lift and a 114-degree lobe separation angle (LSA) and topped off with an aluminum high-rise dual-plane intake manifold. These engines were rated at 345 horsepower. These engines were the first of the factory crate engines that were popular but suffered from a noticeable cold start piston slap due to use of non-offset wrist pin pistons. Subsequent ZZ1 and ZZ2 engines replaced these pistons with offset wrist pins that eliminated the noise.

The ZZ3 and ZZ4 engines replaced the aggressive 235-degree single pattern camshaft with a more subtle 208/221 degrees at 0.050 hydraulic roller with 0.474/0.510-inch lift for the intake and exhaust with a 112-degree LSA. This combination retained the Corvette heads and 9.8:1 compression while the ZZ4 converted to better ovate wire valve springs to better handle the increased lift and valve acceleration rate of this latest camshaft. Engine power for the ZZ4 increased to 355 horsepower at 5,400 rpm with torque at 405 ft.-lbs. at 3,600 rpm. The ZZ4 is still around as a short block, what Chevy calls a partial engine, under PN 12561723.

ZZ5 350 Crate EngineYou are correct that the latest version from Chevrolet Performance is the ZZ5 with some significant changes. The most important is the switch from the old L98 aluminum Corvette heads, which really didn’t flow all that well, to the newer aluminum Fast Burn cylinder heads that were used on the Fast Burn 385, 350-cubic-inch engine rated at 385 horsepower at 5,600 rpm. This engine also used the 208/221-degree hydraulic roller cam. The Fast Burn 385 is no longer available but the head, with its 2.00-inch intake and 1.55-inch exhaust valves and 62cc chambers, found its way onto the ZZ5 shortblock. Combined with a 9.7:1 compression and the same 208/221- degree at 0.050 hydraulic roller, the ZZ5 is now rated at 400 horsepower at 5,600 rpm with 400 ft.-lbs. of torque at 4,000 rpm. The ZZ5 base engine falls under part number 19301293 and comes with an intake, HEI distributor, polished aluminum valve covers, water pump, spark plugs, and a balancer. There’s also a ZZ5 Turn-Key package complete with all the aforementioned goodies, plus a serpentine accessory drive, carburetor, wires, flexplate, and air cleaner under part number 19301294. Plus these engines come with an outstanding 24-month, or 50,000-mile limited warranty. They can offer such a great warranty because from what we hear, the return rate is incredibly low because of their great build quality. For what it costs to rebuild a hydraulic roller-cammed small block, these crate engines are a great deal.


Author: Jeff Smith

Jeff Smith has had a passion for cars since he began working at his grandfather's gas station at the age 10. After graduating from Iowa State University with a journalism degree in 1978, he combined his two passions: cars and writing. Smith began writing for Car Craft magazine in 1979 and became editor in 1984. In 1987, he assumed the role of editor for Hot Rod magazine before returning to his first love of writing technical stories. Since 2003, Jeff has held various positions at Car Craft (including editor), has written books on small block Chevy performance, and even cultivated an impressive collection of 1965 and 1966 Chevelles. Now he serves as a regular contributor to OnAllCylinders.