My rears are close to 3 1/2" deep, because of how far the Sterling full floating axles stick past the brake drums.
And, of course with 4x4 the fronts have to have the correct size hole.
D44 hubs are much smaller that D50/60
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.