GT Performance GM C-Body Parts

Decode, ID, and upgrade your GM 12-bolt rear end. Learn axle specs, gear ratios, and best performance parts upgrades.

Need a little help Identifying GM Body Styles 1964-1972? Click Here!

This resource contains a transmission pan shape ID chart and other tips to help with identifying GM transmissions.

Learn about the power behind the G-body platform and the steps to upgrade a 7.5" bolt rear end to a 8.5" to withstand high horsepower. See how to change the differential fluid and install new gaskets.

Learn how to swap out an LS engine with a modern fuel injected engine into a hot rod for added horsepower, fuel economy, or throttle response. View a list of parts and helpful tips to complete the installation.

Learn about GM alternator identification in our guide. We cover GM 3 wire alternators, 1 wire alternators, and externally regulated so you know what to choose.