Backspacing on a 69 Camaro.

What is the rear backspacing for a 26x11.50x15 for the weld draglites?

Not sure what exactly you are asking for but the section width on those tires is pretty big. I wouldn't think you'd want much more than 4.25" of backspacing.

The previous owner of my car put 275/50/15's on Weld Draglites (15x9.5) with 4.5" backspacing and I have rubbing issues on turns.