weld prostars 15x10 what would be the back spacing on a 86 irocz

6 inches of back spacing would look great with that 15x10 and about 4 1/2 up front

Typically 15 x 10 rims will use 5.5" of backspace on a third gen providing you're using a third gen diff. If you use a fourth gen diff, 7.5" backspace.

sorry not trying yo hijack but what kind of modifications is needed to fit this size wheel and also does anyone have any pics with this setup? if the wheel was bigger lets say a 16-17"x10 would the backspace still be the same?

rim diameter will not change backspace, and since the side wall grows shorter on bigger wheels, clearance should remain the same. I have 15x10 with 5.5 backspace in my sig

hey thanks for all of the info i will try that