metricnut,
I think a better measurement is from wheel mount surface to wheel mount surface. I got a custom made ford 9 inch rear for my 1940 that was 61 inches wheel mount to wheel mount. That should center the wheels up under the fenders if I use a wheel 7 inch wide wheel with 4 inches of backspacing. By using the ford 9 inch floater axle I was able to keep my 6 lug pattern, and get 12 inch disc brakes, All brand new. I paid a premium for this axle, but it was still cheaper than going to the local yards, measuring axles till I found the right one, and rebuilding everything. A lot cleaner too!!!
I hope to be putting that axle under my 1940 soon as well as the new NV4500 transmission and the rebuilt 302 jimmy engine. I'm just gathering a few more parts to make the installation as smooth and painless as possible.
Good Luck
John
