[CC69Rat]

As mentioned, the first thing you want to check is what Rear end housing is in the truck now. 63 (earlier?) - late 70, these trucks had a slightly more narrow housing in them than the later years. The only real way to know is to measure it. 5 or 6 lug doesn't really tell you much. It may have been swapped at some point in its life (?) Just saying I'd measure it.

The easiest way I know to do it, is just lay under the back of the truck. Have your wife, buddy, whatever hold one end of the tape against the back side of the rear brake backing plate. (Assuming drums on the back?) Measure across to the other side in the same spot. If it's roughly 57", you have a later rear end housing. If it's 55.5", it's an early housing.

So, with this in mind the rear housing width can make .75" difference per side, and if the truck is really low it could mean the wheels fit, or.. they don't. Not all the trucks are the same and if you don't have an adjustable track bar on it, I too would suggest one. It will even up the axle housing side to side. That way you're not rubbing on one side, and 2" clearance on the other.

We just need to know which housing you have, and I can make some suggestions for you from there.