The Ford 8.8 and 9 inch rear differentials are two of the most popular and best performing differentials on the market. While the 8.8 inch is commonly used in late-model Mustangs, the 9 inch is certainly the most popular and arguably the most dominant high-performance differential for muscle cars, hot rods, custom vehicles, race cars due to it being a semi floating drop out, with 3600 Gross Axle Weight Rating. Built from 1957-1986, the 9-inch Ford differential is used in a huge range of high-performance vehicles, both Ford and non-Ford, because of its rugged construction, easy-to-setup design, and large aftermarket support. The 9-inch effectively transmits power to the ground for many classic Fords such as the Falcon and F-150, but is also the choice of preference for many GM muscle car owners and racers. Both, however, do need maintaining and rebuilding after extensive use, and need a variety of different ratios for top performance and special applications. This book provides detailed step-by-step information for rebuilding the differentials with the best equipment and installing the gear sets, converting to posi-traction for a variety of applications. Aftermarket 9-ich differentials from different manufacturers like Currie, Moser, Strange are reviewed, and the reader learns how to rebuild and set-up these high-performance aftermarket axles. Chapters include axle identification, inspection, purchasing axles for rebuilding, differential tear-down, ring and pinion gear removal, inspection, reassembly, drive axle choices and more.