Originally Posted by 61EconoPUg
While I was out in the back, I measured a 9" rear end out of a 66 T-Bird, and it is 62" -- a perfect fit for the Econoline! And, with bottom spring perches, it could be used as is, if I wanted to lower the truck! We'll see!
Don't automatically assume you have a 9 inch rear end from a 1966 T-Bird.
1966/72 T-Birds offered
two 9 inch rear ends. One has a 9 3/8" ring gear.
If the 66 has/had a 428 engine...it
is a 9 3/8" rear. If a 390, it could be a 9 3/8" rear.
The Good: 9 3/8" rear ends have 31 spline axles.
The Bad: 9 3/8" rear ends use different axle shafts, carrier and pinion bearings/races, seals, axle and spider gears, R&P's, differential cases than like 9's do.
Beside some 1966/70 cars, the 9 3/8" rear end was available on 1968/72 F100 Camper Specials.
The 9 3/8" rear end was the first Ford rear end to feature 31 splined axle shafts.