Dana to Eaton swap issues

[mikebGMC70]

I have a 1970 c20 that I’m converting from leaf to trailing arms for bag setup. Problem is on the mock up my drive shaft is coming up like 3 inches short. My truck is a long bed with a 4 speed. I was told the rear ends don’t differ on the drive shaft. Is there a difference? Can I move the shaft further from the carrier bearing? Do I need to get a different shaft all together?

I appreciate the help.

[uncle]

I just swapped from an Eaton to Dana in a longhorn and had to get rear shaft cut,so yes that sounds right.