[Palf70Step]

Yes it was a 12 bolt rear. From what I was told it depends on the year. My 64's rear end it would take the 3.08 from a 72 rear (just remembered i had. Pinion ring and carrier from the 72 ) Although bearings and all were a 1 year only thing, so made it harder to find and of course pricier.

and yes, I did it for the highway cruising as I was hooked to a manual 3 speed. Down here you don't need lot of gear unless you are towing as it is pretty flat.