It's a simple one that I just need a definitive answer to, i have searched and found some hearsay and conflicting information answers. Here goes:

If I get a 7" Sierra Open diff that has bolt on driveshaft stub shafts, can I take those stub shafts out and put standard (26 spline) push fit driveshafts straight in?

Has anybody actually done it? I just want to find out before I make a purchase.

Not interested in LSD's, or hybrid shafts or swapping bits of bearing.

There are several push in shafts and several bolt on derivatives
We tried putting bolt on stubs on a push fit diff and they fouled the planet gear cradle
You can then grind back the end of the stub to make it free
You can make the shafts hybrid with bolt on one end and push fit the other but you have to be very specific with shaft thickness and diameter.
Seventh heaven is a good source of real dimensions but you'll have to dig through a lot of information

I recently did the opposite.
I had a bolt on 3.62 diff and purchased a 3.38 push in diff - both 7"
I took the stubs from the 3.62 and put them in the 3.38.
Only problem was when I put the circlips on the stubs, things were a bit tight, effectively making the diff locked.
Making the circlips thinner fixed that issue.
So it would seem that you could easily go the other way as long as the splines are the same.
The 3.62 diff I had was from a 2.0 Ghia wagon with disk brakes. No idea what the 3.38 came out of.

David