12 Bolt axle
I'm not sure, but if you're talking about the ENTIRE rear end axle housing, I think it will fit. I installed a '72 in a '71 truck and it was a perfect swap. If you have a good 12 bolt/6 lug now, you can replace just the axle's with 5 lug aftermarket axle's? If you do the swap, measure your existing housing width from backing plate to backing plate (or axle face to axle face). If this matches, measure the points on the housing where the spring centers mount. Compare these with the same on the new housing. If they match, I think you're OK to do the swap! Good luck.