I had a 1978 F250 Dana 60 that I got with mystery miles and history. I used the stock 3.54 gear from the junk yard doner for about 5 years with a Dr. Diff spool before it started making noise and I replaced it this spring.

3740lbs with me in it, 275/60 dragradial, off the transbrake every pass. Street/strip use.. It's been a best of 1.37 60ft.