The Chevy 12-bolt axle shaft (left) is tapered; the Ford 9-inch shaft is the same diameter throughout its length, except for the short section just after the spline end. This makes it easy to narrow ...

For over half a century, the Ford 9-inch rearend has been the king of aftermarket axle upgrades. Few other axles enjoy the same amount of bolt-on and custom componentry. The Ford 9-inch is a great ...

Sooner or later, it boils down to what direction you're going to go when your Mustang's rear axle wears out. Some decisions are straightforward. If you have a six-cylinder Mustang, stick with the ...