Chevrolet Performance ZZ632 Crate Engine: 1,004 Horsepower in a Box

There is no replacement for displacement, so the saying goes. Chevrolet Performance apparently agrees as its ZZ632 big block Chevy displaces 632 cubic inches—that’s 10.4 liters—making it the biggest crate engine GM has ever built. It’s also the most powerful; the naturally aspirated engine makes 1,004 peak horsepower at 6,600 RPM and 876 lbs.-ft. of peak torque at 5,600 RPM on 93 octane pump gas. And it comes to you in a big box, fully assembled and ready to drop between the fenders of whatever you deem worthy of such an engine.

Let’s see what makes the ZZ632 tick.

Block and Rotating Assembly
The ZZ632 uses a Bowtie Sportsman tall deck iron block with four-bolt main caps, similar to the one that underpins the ZZ572 crate engine in the infamous COPO Camaro. The block has 4.60 inch cylinder bores and is clearanced for the big 4.75 inch stroke crankshaft.

The rotating assembly features a forged 4340 steel crankshaft, forged steel H-beam connecting rods, and forged 2618 aluminum pistons. This alloy is more ductile than the 4032 alloy used in other performance pistons. That means the pistons in the ZZ632 are much more resistant to detonation encountered in racing, especially if you add a turbo, supercharger, or nitrous oxide. Static compression is 12.0:1.

Camshaft and Cylinder Heads
The camshaft is a billet hydraulic roller rated at 0.780 inch intake/0.782 inch exhaust lift and 270° intake/285° exhaust duration @.050 inch of valve lift. That’s a big cam.

The RS-X Symmetrical Port aluminum cylinder heads are named for Ron Sperry, the GM engineer who designed them. Taking a page from Pro Stock drag race head design (think the Olds DRCE heads from the 1990s) and the original LS1 heads he also designed, Sperry gave the CNC-machined RS-X heads symmetrical intake and exhaust ports. Unlike traditional big block Chevy heads with unequal intake port shapes from cylinder to cylinder, the RS-X’s ports are all the same length, volume, and spacing. That means all ports flow the same amount of air and fuel with no starvation issues. Equalized intake ports should also make fuel system tuning easier.

The RS-X cylinder heads have 70cc combustion chambers with 2.450 inch intake/1.800 exhaust titanium valves, and are fitted with 1.8:1 ratio forged aluminum, shaft-mount roller rocker arms. The exhaust port design will require custom headers.

Intake Manifold, EFI System, and Ignition System
The high-rise, single plane intake manifold is fitted with a Wilson Manifolds 4500-flanged throttle body and is set up for port fuel injection. The injectors are rated at 86 lbs.-hr. The ZZ632’s has a pre-programmed, self-learning engine control system to make tuning a no-brainer. The 58X crank-trigger ignition system has ignition coils mounted on a special valley plate.

Other Components
The Chevrolet Performance ZZ632 comes fully assembled with an eight-quart oil pan, aluminum water pump, an ATI SFI-approved harmonic balancer, and cast aluminum valve covers with embossed 632 logos. They’re Chevy Orange so you can’t miss them.

Chevrolet Performance says you’ll need to come up with a compatible starter, a high-pressure electric fuel pump, and an air cleaner. An air cleaner that matches the ZZ632’s valve covers will be available from Chevrolet Performance. You will also need an internally balanced flywheel if you’re using a manual transmission.

One more thing—the Chevrolet Performance ZZ632 crate engine is for racing and off-road use only.

SEE THE CHEVROLET PERFORMANCE ZZ632 CRATE ENGINE AT SUMMIT RACING