Will these wheels/tires fit stock 69 Cuda springs

69 M-CODE CUDA said
New wheels have a 4-1/4” backspace.

Stock SBP on an 8-3/4 axle.

how does your car sit in the rear?

original quarters?

I’ve run 15x8 with 4.5 backspace with 245/50/15 tires on my 68 Barracuda with SBP axles (just drilled for LBP). A 275/60/15 will have a lot more sidewall bulge.

It will be really close.