Of course, actually measuring it is the BEST course. But, that said, I believe the axle width, wheel mounting surface (WMS) to WMS is about 60" inches or so. I base that on having a few Mopars, including a '55 Chrysler that is in the 60"/61" range. There are a number of axles that are in that range and that have 5 lug by 4 1/2" bolt pattern. Many Ford 8", 9" and 8.8" axles.....Quite a few Mopars, including Jeep, but get one from a Mopar with rear axle parking brake, not driveshaft brake, in case you eventually upgrade the transmission and lose the current parking brake.