What was the backspacing on the 1970 factory 15x7 inch Z28 rims? I'm trying to figure out what backspacing to buy for my new wheels. I'm going to be putting some 16x8 Torque Thrust II wheels on my 1970 Camaro. I'll be running 245s or 255s with a 50 series profile.

 

This might be of some help

http://www.nastyz28.com/2gcog/stegmiller/tires.htm