Rear end interchanges?

[VA72C10]

I am looking for a posi rear for my 70. I know that 67-69 had narrower rears than the 70-72. And I've read that 73-87? Had 12 bolts that would also work (just have to weld the trailing arm bracket on) My question is in regards to 60-66 trucks....do those rear ends interchange onto a 67-72? Are they the same as 67-69? I am looking at a 66 project truck with a freshly rebuilt 411 posi...thinking of switching that rear for mine and then putting mine in the 66....The cost of the truck is what many are charging for just the posi rear.

I haven't gotten to see the truck and may never but want to know what rears will fit so when I'm scrounging craigslist I'll know what to consider. I did check the FAQ's and tried a few searches but didn't find this info. Thanks in advance.

[leftcoast66]

Yes the diff'll fit. Watch out for bolt circle's ofcourse, not sure what yours is and if that one's been switched to 5x5 or not. It'll need to have different mounts put on if yours isn't a trailing arm setup, because its a trailing arm rear end. Other than that, its I a couple inches narrower than the later ones, but not sure what year it switched lengths. Hope that helps, I'm sure someone'll fill in the blanks on years and such as I can't remember those details right now.

[N2TRUX]

FYI- Not all 73-87's had 12 bolt. They started going to 10 bolt in the late 70's.

[SCOTI]

10-bolt after 81.
60-66's could be 12-bolt 30-spline or 17-spline.
60-64's also came w/the old 'drop-out' style differential that was different vs. the 'traditional' 12-bolt housings.

Panhard bar mounts are different on the earlier housings. Aftermarket 'long' PHB's relocate the bracket so that's not that big of a deal on the keeper, but something to consider on the one you'll try to re-sell.....