So if simple math wasn't your thing in school, then narrowing a Ford 9-inch at home might not be the job for you. But if you're the type of hot rodder who likes a challenge, then this old-school ...
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 ...