Is it not the case where the ring gear will bolt to it but the gears cannot be set up at all because the 5:87's require a 4 series carrier. If a 70 is the same as a 60, 4:10 gears require a 3 series carrier or diff. I'm setting up a front dana 60 in my wagoneer right now with 4:10's mounted on a 3 series Powr-Loc.
If you take a 3 series carrier and a 4 series carrier and set them side by side with the ring gear casting down you will see about a 3/16th difference in height of the machined surface the ring gear bolts to between the two carriers. That step is why 3 and 4 series gears and differential's won't work together.
Hopefully he is talking about a Powr-Loc. They are one of the best. Been around for 35 years.
Liz, covid, murdered 10/19/21