Admittedly few of you will make use of this, but it's worth consideration. The 8.8 swap is done for strength, because our '90.5-up 7.625" 28-spline tends to hurt the R&P rather than the stock 28-spline axle shafts. The aftermarket offers even stronger 28-spline shafts. Earlier Ford 8.8s were 28-spline, later most changed to stronger 31 spline shafts. Even so, these tend to fail before the R&P, even with aftermarket shafts. But there's another strength difference that never caught my attention until now: 28-spline Traction-Lock differentials used a 0.750" cross-shaft, while 31-spline got upgraded to 0.875". If you buy an ARB, it comes with an even stronger cross-shaft, but if you're doing a "Lincoln Locker" correctly, then cross-shaft strength loses most of its important. For mostly-street use with drag radials, a Traction-Lock with a Ford Racing ( FRPP ) rebuild kit is plenty adequate. Welding a diff does not belong on the street, ever.

 

Didn't know the cross-shaft upgrade. I'd like to do an 8.8" for a car "in which it doesn't belong" but don't plan on lincoln-locking; preferably a truetrac.