Ok, I don't have the truck here too measure so thats why I'm asking. I was too take the crappy diff. out of a 76 d100 and put in a 8 3/4. I can't find one out of the earlier 70's trucks so I was wondering if anyone has the hub to hub width of mine and one out of say late sixty's truck and also what the centre too centre of the spring perches are? I would think the older one is alittle narrower but thats fine. Just need too compare since I have access too a whole pile of those and I think they are around $100! I was also told a c-body diff. was the same width and I just have too move the perches????? I only heard that once so I don't know if thats true or not.