78 rears in a 70

[7084Driver]

I bought a set of matching rears (14bolf ff and dana 44) from a 78. I noticed the rear end itself is 2.5" wider than the dana 60 that came in the truck and that i will have to move the spring perches and shock mounts. Would it be an issue if each wheel stuck out another 1.25 inches on each side. From my measurements the front will bolt right in fine, can anyone shed any light on the subject?? Thanks RYAN