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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
Displacement632 cu in (10,348 cc)
Bore x Stroke4.60 x 4.75 in
Compression Ratio12.0:1
Power1,004 hp @ 6600 rpm
Torque876 lb-ft @ 5600 rpm
Maximum Recommended Engine Speed7,000 rpm
BlockTall Deck 632 Bowtie Sportsman, cast iron, four-bolt main caps
Cylinder HeadsRS-X Symmetrical Port, CNC-machined aluminum
CrankshaftForged steel
Connecting RodsForged steel
PistonsForged aluminum
FuelElectronic port injection

Written by Manoli Katakis

Muscle Cars & Trucks was founded by Manoli Katakis - an automotive media veteran that has been covering the latest car news since 2009. His journalism has uncovered dozens of major product changes, updates, plans, and cancellations long before automakers were ready to make things official.

Some highlights over the years of his reporting include the uncovering of the Zora trademark before anybody else reported on the coming of a mid-engine Corvette, as well as the dead-accurate reporting of the coming of the Chevrolet Colorado ZR2, two years before it hit the market, and even before the debut of the concept vehicle. This type of reporting has immediately continued here, with reports of the original seventh-generation Camaro plans being shelved, as well as what's in store for the Chevrolet Silverado.

Some of his work can be found on massive automotive media outlets, such as Motor1. He also has been a guest on the 910AM Radio Station with Detroit News auto critic Henry Payne, as well as the enthusiast-oriented Camaro Show podcast.

Over the years, Manoli has interviewed various automotive industry titans, leaders, and people that make things happen otherwise. These include figureheads such as GM CEO Mary Barra, GM President Mark Reuss, automotive aftermarket icon Ken Lingenfelter, Dodge firebrand Tim Kuniskis, along with various chief engineers of vehicles such as the Ford F-150 & Mustang, Chevrolet Camaro & Corvette, and many more.

At MC&T, Manoli is taking his journalism expertise, deeply planted sources, driving abilities, and automotive industry knowledge to new levels, covering more vehicles and brands than ever before. This is the place where you will continue to read groundbreaking stories about American performance vehicles, pickup trucks, and sport utility vehicles. Here is where you’ll also read insights and quotes from various automotive subject matter experts on the latest relevant products, as well as some of the latest official news from their manufacturers.

Fun facts: he also once beat Corvette Racing driver Tommy Milner in an autocross with a Chevrolet Bolt EV. The biggest vehicle he’s ever driven is a John Deere mining truck. Besides a go-kart, the smallest vehicle he’s driven has been a Hyundai i10. He’s also spent time in the cockpit of various American performance vehicle icons, including the fifth-generation Chevrolet Camaro Z/28, Dodge Challenger Demon, and Ford Mustang GT350R. He has reviewed dozens of trucks, SUVs, and performance vehicles over the years.

One of his favorite new vehicles on the market today happens to be the Chevrolet Colorado ZR2 Bison. He is also a card carrying member of the Sports Car Club of America, and regularly participates in Detroit Region autocross events.

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