I swapped out the original 14" SSII wheels for a set of 15" cragar ss wheels. Problem is on tight turns, like when parallel parking or making a u-turn, my front wheels are rubbing badly on the inner fenders, at the bottom on the rear side of the wheel wells..

Never had this issue with the 14" wheels. And I can't imagine not being able to run a 15" wheel..
I removed a wheel, and it seems I have 4 back rims.. they are all deep dish.. I measured roughly 2" from the lip of the rim to the backside of the mount/hub.. so the backpacking is like 2"...
What is the correct backpacking I need on the front for a 15"wheel?
Tires are 215/60r15 all around. Gonna try and find a pair of 15x7 wheels...
Otherwise just put back 14s if I cant find them reasonably priced.

Thanks

Oh, btw.. it's a 1978 cutlass..2dr..stock front end.