Gen 3 5.7L Aluminum Engine Block

The GM 12559378 is a Gen. 3, 5.7L (346 cubic inches) aluminum engine block, commonly referred to as the LS1. This block is designed with centrifugally cast iron liners and utilizes 6-bolt main caps for enhanced strength and durability. This engine block is a key component for performance builds and replacements. It has a bore of 3.90 inches and a stroke of 3.62 inches, with a compression ratio of 10.1:1. The camshaft specifications include an intake lift of 0.478 inches and an exhaust lift of 0.524 inches, with durations of 204 degrees intake and 211 degrees exhaust. The GM 12559378 engine block is identified by various casting numbers, including 12550592, 12559846, 12559090, 12560621, 12562174, 12560629, 12559378, 12559846, 12560626, 12561166, and 12561168. It is often found in performance-oriented vehicles and is suitable for engine swap projects. This LS1 block was utilized in various General Motors vehicles from 1997 to 2004. Specific applications include the 1997–2004 Chevrolet Corvette, 1998–2002 Chevrolet Camaro (Z28/SS), 1998–2002 Pontiac Firebird/Trans Am, and the 2004 Pontiac GTO.