This is number #79 of the 427 examples of this engine that were made after the tooling to produce the original ZL1 427 was rediscovered decades after it had been tucked away in a warehouse.
While horsepower of the ZL1 was officially rated at 430 bhp many claimed it was actually turning out over 500 bhp. It was also notably lighter than almost all other big block V8s thanks to the fact that it had an aluminum block and heads.
This is number #79 of the 427 examples of this engine that were made after the tooling to produce the original ZL1 427 was rediscovered decades after it had been tucked away in a warehouse.
History Speedrun: The GM “Anniversary Edition” 427 V8
In 2008 GM Performance Parts lit the American automotive performance world on fire with their release of the the Anniversary Edition 427 – it was a limited-production, all-aluminum big-block crate engine built to commemorate the 50th anniversary of the Chevrolet big block V8.
The engine (sold as part number 19166392) was a modern re-creation of the borderline-mythical ZL1 427, the most powerful engine General Motors ever offered to the public in the 1960s, and perhaps best of all, it was made using the original 1969 ZL1 block tooling.
The ZL1 Tooling Rediscovery
The original ZL1 aluminum blocks made in-period had been cast by the Winters Foundry in Canton, Ohio, they were made from the late 1960s through until 1974. After production ended, the block casting tooling was set aside and eventually mixed in among obsolete equipment at the foundry.
Years later, while clearing out a batch of old tooling, workers at Winters stumbled onto the original ZL1 patterns and molds. They were found to be in remarkably good condition, likely because relatively few blocks had been cast from them over their production life, leaving the tooling well within its useful lifespan.
The discovery was first reported in Vette Magazine’s September 2001 article “Born Again Big-Block.” GM Performance Parts initially used the recovered tooling to produce bare ZL1 blocks for individual sale (as part number 12370850), before developing the full Anniversary Edition crate engine.
The GMPP division oversaw the restoration of the tooling and updated some design features of the block casting, including the addition of screw-in galley plugs and strengthening in key structural areas. After the 427th Anniversary Edition engine was produced, the tooling was permanently retired.
This GM Performance Parts Anniversary Edition 427 crate engine is number 079 out of the limited production run of 427 examples built to mark the 50th anniversary of Chevrolet’s big-block engine family.
The Original ZL1
The story of the ZL1 really begins in 1969, at the height of the muscle car wars. The ZL1 was an all-aluminum 427 cubic inch Mark IV big block developed for Can-Am racing. It had an aluminum block with cast-iron cylinder sleeves, aluminum heads, a solid-lifter camshaft, a 12.0:1 compression ratio, and a single Holley four-barrel carburetor.
GM officially rated it at 430 bhp, but real world output was well above 500. Each engine was hand-assembled in a climate-controlled room at the Tonawanda plant and carefully broken in on a dynamometer.
The ZL1 was never intended for street legal vehicle use. Illinois dealer Fred Gibb, working with Chevrolet Product Promotions Manager Vince Piggins, used the Central Office Production Order (COPO) system (normally reserved for fleet vehicles) to install ZL1 engines in Camaros, circumventing GM’s ban on engines over 400 cubic inches in non-Corvette models.
Only 69 ZL1 Camaros and two ZL1 Corvettes were built. The option added $4,160 to the sticker, back then this was more than the base price of the car itself.
The Anniversary Edition
For the 2008 Anniversary Edition, GM Performance Parts cast new aluminum blocks from the recovered original ZL1 tooling, then paired them with modern internals and a revised top end. Only 427 engines were produced before the tooling was permanently retired.
Key Engine Specifications:
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- Displacement: 427 cubic inches (4.250″ bore × 3.760″ stroke)
- Block: All-aluminum, 4-bolt main caps
- Rotating assembly: Forged steel crankshaft, forged steel connecting rods, forged aluminum pistons
- Compression ratio: 10.1:1
- Cylinder heads: Aluminum oval-port, 110cc chambers, 2.19″/1.88″ valves
- Camshaft: Hydraulic roller (.510″ intake / .540″ exhaust lift)
- Rocker arms: Aluminum roller, 1.7:1 ratio
- Induction: Aluminum oval-port intake with 870 CFM carburetor
- Ignition: HEI distributor
- Rated output: 430 bhp at 5,800 rpm / 444 lb ft at 3,800 rpm
- Recommended fuel: Premium pump gas
While horsepower of the ZL1 was officially rated at 430 bhp many claimed it was actually turning out over 500 bhp. It was also notably lighter than almost all other big block V8s thanks to the fact that it had an aluminum block and heads.
The most significant modernization was the hydraulic roller camshaft, replacing the original ZL1’s mechanical flat-tappet cam. This improved street drivability and eliminated the need for regular valve-lash adjustments while maintaining excellent performance. Like the 1969 engine, the rated output is widely considered conservative, with true power believed to exceed 500 bhp.
Each engine shipped in a wooden crate with a numbered certificate of authenticity, engine data plaque with a serial number matching the valve covers, and Anniversary 427 fender emblems. MSRP at launch was $28,625 USD. The engine was designed for pre-1976 street vehicles or any off-road vehicle, though not for marine applications, and was backed by GM’s 24-month/50,000-mile crate engine warranty.
GM also offered the ZZ427 (part number 19166393), a regular-production companion engine sharing the same top end but built on a cast-iron block at a lower price point.
Remaining unused Anniversary Edition engines are rare collectors’ items nowadays, with most of the 427 produced having been installed in COPO Camaro recreations, Corvette resto-mods, and other big block Chevrolet and GM family projects.
The GM Anniversary Edition 427 V8 Shown Here
This GM Performance Parts Anniversary Edition 427 crate engine is number 079 out of the limited production run of 427 examples built to mark the 50th anniversary of Chevrolet’s big-block engine family. As you would expect, the block is an all-aluminum piece cast from the original, refurbished 1969 ZL1 tooling.
This engine has never been fired up or installed in a car, and remains in its original factory shipping crate – it’s been in the current seller’s possession since October of 2025.
As noted higher up, this V8 has a forged steel crankshaft, forged steel connecting rods, and four-bolt main bearing caps, while the pistons are forged aluminum units delivering a 10:1 compression ratio. The valvetrain runs a hydraulic roller tappet camshaft paired with aluminum roller rocker arms, and the engine is designed to operate on readily available 92 octane pump fuel. A flex plate is fitted, and ignition is handled by an HEI distributor with spark plugs and wires included.
Up top, the engine wears aluminum oval-port cylinder heads matched to an aluminum oval-port intake manifold. The fronts of the heads are machined smooth and inscribed with the “GM Performance Parts” logo. It also has a cast aluminum water pump, a Chevrolet-logo oil filler cap, and a chrome oil breather with a filter. Engraved plaques on both cast-aluminum valve covers identify this specific engine as number 079 of 427.
The engine comes with an owner’s registration kit is also part of the package, along with a numbered leather jacket embroidered to match the engine’s build sequence, rounding out what amounts to a complete, as-delivered collection from GM Performance Parts.
The sale includes a Holley carburetor that was supplied with the engine at the time of original purchase, a certificate of authenticity, and the factory shipping crate.
An owner’s registration kit is also part of the package, along with a numbered leather jacket embroidered to match the engine’s build sequence, rounding out what amounts to a complete, as-delivered collection from GM Performance Parts.
The engine is now being offered for sale out of Rockwood, Tennessee on Bring a Trailer and you can visit the listing here if you’d like to read more about it or register to bid.
Images courtesy of Bring a Trailer
Articles that Ben Branch has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
