Seems Like GM Isn’t Done With Engines, And We’re Here For It

Chevrolet Performance 10.4L ZZ632 1004 horsepower big block v8 engine 2021 sema show 632 cubic inch
Image via Chevrolet

In recent years, Mopar and Ford Performance seemed to have had enough with Chevrolet and its crate engine supremacy. LS-swapped this and LT4 that. Race engines, emission compliant engines, and transmissions, too. Indeed, Chevy has the crate engine market under lock and key, but lately, not so much the headlines. In the past two years or so, magazines and blogs started to read about 1,000 horsepower Mopar Hellephant swaps, and Ford Performance 7.3L Godzilla V8 swaps in everything from muscle cars to Jeeps, and even vans. Today, Chevrolet Performance reminds everybody why they dominate the crate engine space, with the announcement of the 1,004 horsepower, 10.4L (632 cubic inches) ZZ632 crate engine. Did we mention it’s all motor? No forced induction here, giving credence to the old adage: there’s no replacement for displacement. Best of all, it runs on 93 octane pump gas. It’s an absolute battle axe of an engine.

2021 SEMA Show Chevrolet Performance ZZ632/1000 ZZ632 10.4L big block v8 crate engine horsepower torque
Image via Chevrolet

1000+ HP Chevrolet Performance ZZ632 Crate Engine: The Details

This extra Big Block V8 reaches peak power at 6,600 rpm and revs to a recommended maximum of 7,000 rpm. We’ve never heard of any engine this big, spinning this fast. But if one of you out there know of one, let us know so we can write about it.

The fueling system of the ZZ632 is made up of eight port injectors with the engine breathing through CNC-machined high-flow aluminum cylinder heads featuring symmetrical ports. No direct injection here. By comparison, the Hellephant and Godzilla V8 also utilize port fuel injection systems. They’re both also iron block pushrod V8 engines. Such is the winning recipe for reliable power.

Furthermore, while older Chevy Big Block fuel system designs have variations in port shape from cylinder to cylinder, all eight intake ports of the ZZ632 have the same length, volume and layout. Similarly, all of the ZZ632’s exhaust ports are identical. This symmetry ensures individual cylinders all produce similar power.

These symmetrical port cylinder heads also have a special codename that GM performance enthusiasts my smile at: RS-X. This is said to be named after powertrain engineer Ron Sperry, who designed them as one of his final accomplishments in more than 50 years working on General Motors performance and racing engines. Sperry’s accomplishments also include introducing symmetrical ports to the Small Block V8 engine family with the LS1 engine that debuted in the 1997 Chevrolet Corvette, and has been *the* crate motor of choice for engine swappers due to its incredibly compact packaging, low price, and great power density for the weight.

To handle 1,004 horsepower and 876 lb-ft of torque, the Chevrolet Performance ZZ632 crate engine block is made of cast iron, sharing a mold with the nearly-as-mighty ZZ572 crate engine, but the castings are machined to accommodate the incredible 632 cubic inch displacement. The bore grows by 0.040 inch compared to the 572-cubic-inch ZZ572 V8, with most of the displacement gain coming from a stroke that’s 0.375 inch longer than the ZZ572.  Both the block and the connecting rods had to be modified to fit the long stroke, while four-bolt main caps and a forged rotating assembly ensure strength and durability.

To test its durability, a single engine endured more than 200 simulated drag strip passes on a dynamometer. Not bad. Now, if only somebody would like up a ZZ632 Big Block in a race against a Mopar Hellephant V8 and the upcoming Godzilla V8-based Megazilla engine from Ford Performance.

You can bear witness to the Chevrolet Performance ZZ632 V8 crate engine at the 2021 SEMA Show in Las Vegas, Nov. 2–5, with participating dealers beginning deliveries in early 2022. Check below for the rundown of mechanical specifications.

ZZ632/1000 Specs

Chevrolet Performance ZZ632/1000
Displacement 632 cu in (10,348 cc)
Bore x Stroke 4.60 x 4.75 in
Compression Ratio 12.0:1
Power 1,004 hp @ 6600 rpm
Torque 876 lb-ft @ 5600 rpm
Maximum Recommended Engine Speed 7,000 rpm
Block Tall Deck 632 Bowtie Sportsman, cast iron, four-bolt main caps
Cylinder Heads RS-X Symmetrical Port, CNC-machined aluminum
Crankshaft Forged steel
Connecting Rods Forged steel
Pistons Forged aluminum
Fuel Electronic port injection

Written by Manoli Katakis

Detroit Region SCCA Member and founder of MC&T. Automotive Media Jedi Knight. Not yet the rank of Master.


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