looking for 325 50 15 tires

You could do what I did. Grab a tire that is spec'd to the same diameter. Mount it, install it , settle the suspension, and back-engineer the fit. Not 100% accurate, but worked for me.They fit in a 68 Barracuda wheelhouse, even lowered a bit, with careful centering. And a little pounding of the inner liner, and moving the diff back about 3/8 on the front perchs.(all the stud-length will allow.) Take it easy on the turns, 'til you get it sorted.