Will 15" x 10" wide rim with 4" backspace fit with stock rear?

[88Stanger]

I am building a 1966 short bed fleet side from the ground up and i am just wondering if a rim that is 15" x 10" wide with 4" backspace fit between the outer rear fenders? I can modify the bed and rear inner fender wells, just not sure if it will fit in between the outer fenders.
Sorry to ask, i have searched and searched and i cannot measure because the truck is completely apart.

Thanks to all who give feedback, very much appreciated.

Just a note, plan is fully bagged, tubular front a-arms, factory short bed, wood bed, fleet side, 383 full roller stroker, rebuilt muncie 4-speed and so on. build page coming....