GM Anniversary Edition 427. All-Aluminum Big Block. Only 427 of these 427ci engines built! 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 ultimate 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 a retooled version of the ZL1 aluminum block using the exact same tooling that helped create this legend in 1969. The advantage of the aluminum block is that it offers the completed engine the weight of a small block with a whole lot more power. The block offers a full-strength structure including 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 9.5:1 final compression ratio. Aluminum, oval port heads have a 110 cc combustion chamber and carry 2.19-inch intake and 1.88-inch exhaust valves. A matching, high-flow aluminum oval-port intake feeds the heads with the help of an 870 cfm carburetor. The camshaft is a hydraulic roller with valve lift numbers of .510-inch on the intake and .540-inch on the exhaust. We even added 1.7:1 aluminum roller rockers. Like the original ZL1, the Anniversary 427 comes grossly underrated at 430 horsepower.
With a full list of features, this modern ZL1 is one of the most exclusive big block crate engines ever offered by GM Performance Parts. But, we didn't stop with just a great engine! 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. To document the rarity of this engine, GM Performance Parts will include a complete owner's kit with each of these engines. In that kit, you'll find 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.
Only 427 of these crate engines will ever be produced, and then the ZL1 tooling will be retired forever. We hope that you will be one of the elite hot rodders to celebrate the anniversary of the big block Chevy with GM Performance Parts.