Chevrolet Corvette Zr1 Ls9 Engine Block

Just another innocuous building tucked at the back of a Wixom, Michigan industrial park, GM’s Performance Build Center offers few clues to the magic happening inside. Behind the doors, though, some of GM’s most skilled workers are crafting the beating hearts of the company’s best cars. This is the birthplace of the Corvette’s most potent engines.

The handbuilt engines from PBC will eventually land in one of three Corvette models. For the ZR1, there’s the supercharged, 638-horsepower LS9.; Z06 ‘Vettes are powered by the 7.0-liter, 505-horsepower LS7. The 430-horsepower LS3 engine of the manual coupe Corvette Grand Sport is Wixom’s most recent undertaking. While the specs might lead you to believe this engine is the same as that in a base Corvette, it features a forged crank, tri-metal crank bearings, and a dry-sump oil system. It’s that performance lubrication setup—specifically the crankshaft-mounted oil pump—that calls for production of these unique LS3s in Wixom.

By any standard, modern automotive assembly plants are impressively organized, clean, and ultimately unextraordinary. Despite that, the Wixom build center makes engine building look as tranquil, delicate, and calculated as fine knitting. There’s a library-like quiet at PBC in place of the rhythmic machinery and tedious warning chimes of a high-production line.

The engine builders – there are sixteen of them – are some of General Motors’ most skilled workers. Several have worked as experimental engine builders for GM, where they machined metal with extremely tight tolerances to build engines from scratch. But it’s not just their skill that qualifies these craftsmen to build such special engines. The builders are also extremely passionate about Chevy’s sports car. Many own a ‘Vette, and one particular builder is known for keeping watch on Internet forums to ensure the build center’s work is performing in the hands of owners. The storied history behind the engines is also kept close. Just outside the entrance to the workshop floor, a small, informal museum traces the modern engines’ roots back to the first small block V-8 of 1955.

It’ll take a builder roughly three hours to complete an engine. A rolling cart holds the block and moves with each builder down a 200-foot line as innards and appendages are collected and attached. The torques on every fastener are verified three times during the build using a computer system to ensure no engine leaves with an improperly tightened bolt. After an engine is completed, two final unique checks are made on the handbuilt powerplants. A cold test spins the crankshaft without firing the engine to verify the mechanicals are in order. Finally, each engine is started and the crankshaft is balanced with small weights at either end of the block. Then engines, bearing the signature of their builder, then travel to Bowling Green, Kentucky to breathe life into a new Corvette.

By Eric Tingwall