I got a quick question. Will a Ford nine inch from a 80's truck fit a 74 F100? The axle housing is 3" longer on the 80's model housing. This will make the tires stick out 1.5" on each side??? I thought the axles would interchange, but do the axles have a room to move out or in?

 

IF the housing is wider, you must use the axles for that housing. There is no wiggle room, esp. not 1.5 inches per side. You also need to check the spline count to see if your center section and the axles are both the same count, 28 or 31. Bearing size also is an issue, so check that as well. (End of axle tube)

But first, check the spring pad to spring pad measurements. Some wiggle room here, but beware.

Do you have clearance in the wheel wells with your current tire/wheel?