Wheel and Tire fitment

Hello there,

Looking to buy a set of Weld or Centerline wheels for my 71 Chevelle.
I want to put as much tire under the rear as possible without modifying the frame. I was told I could squeeze a set of 15 x 10's with a 5 1/2" backspace under the car. Anyone have any suggestions?

Currently the car has the 15 x 8 corvette rally wheels with L-60-15" inch tires.

I have a 69' with 15 X 10's and my back spacing is 6 1/4" I looked long and hard to find these and they are perfect on my car I couldn't fit them with any other spacing. I done a lot of research on this subject and got it right I hope you can too