The year was 1969, and the musclecar wars were in full swing. Each one of the big three had developed their own version of the ultimage high performance big-block engine. Then, GM unleashed the ZL1, the most powerful engine ever released by General Motors. Based on an exotic aluminum block, the ZL1 offered only the best components from the L88 engine including a high compression piston, high flow aluminum heads and intake, and a bombproof bottom end. To celebrate the 50th anniversary of the Chevrolet big-block, GM Performance Parts has brought back a modern version of the ZL1 for your chance to relive musclecar history.

The Anniversary Edition 427 starts with the ZL1 aluminum block using the tooling that helped create this legend in 1969. The block offers a full-strength structure, thick deck surfaces and 4-bolt mains. Building on that foundation, the short block contains a forged steel crank, forged steel rods, and forged aluminum pistons for a 10.1:1 final compression ratio. Aluminum oval-port heads and matching high-flow aluminum oval-port intake are paired with an 770-cfm carburetor. The camshaft is a hydraulic roller with valve lift number of .510" on the intake and .540" on the exhaust. We even added 1.7:1 aluminum roller rockers. Like the orginal ZL1, the Anniversary 427 comes grossly underated at 430 horsepower.

Once you purchase an Anniversary 427 big-block crate engine, you enter a very exclusive club because only 427 of these engines will ever be produced. A special owner's kit includes official Anniversary 427 emblems to place on your car, as well as an engine data plaque and certificate of authenticity that share a matching serial number with the valve covers. Made in the USA.

Only 427 of these crate engines will ever be produced, and then the ZL1 tooling will be retired forever.

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