Rear Axle Housing Flange ID Chart - Ford 8.8, 9", Mopar, Chevy 12 Bolt, Dana 60

This document is a rear axle identification reference chart. It instructs readers on how to correctly identify a rear end assembly using three key measurements: outside bearing diameter, housing flange dimensions, and the stud pattern/bolt circle on the axle flange. It cautions that custom rear ends may use axle bearings and housing flange patterns different from original equipment, and that the actual rear end may differ in appearance from the diagrams, so measurements should be relied upon for certainty. The chart presents ten labeled housing-end flange diagrams with dimensional callouts (in inches): Small Ford, Big Ford, Big Ford (New Style), 8.8" Ford, Chevy (Special), 8-3/4 and 9-3/4 Mopar / Dana 60, Olds/Pontiac, 8-1/4 and 9-1/4 Mopar, Mark Williams, and 12 Bolt Chevy, plus an axle flange cross-section diagram showing offset. Each diagram shows bolt hole positions, flange outline shapes, and diameters such as bearing bore diameter (commonly 3.150 DIA) and bolt spacing dimensions. A reader can use this chart to compare measured dimensions from their own axle housing ends against these known factory patterns to determine which manufacturer's rear axle they have, which is useful when sourcing axles, bearings, retainer plates, or brake backing plates.