Does anyboby know what the code is for 15x8's with 4.5 backspacing vs 4.0 backspacing. All I could find was this site http://www.geocities.com/MotorCity/Flats/8941/Rally.htm
What backspacing is a AZ coded wheel?
I'm looking for 2 15x8's for the rear on my 67. I've read on here that 4.5 BS fit better compared to 4.0 BS. Is this true?

I could not find any factory 15X8 with 4.5 BS, I bought my 15X8 4.5 inch BS rims from NPD. You could probably get a set of 15X8 4 inch BS rims from a corvette and get the centers re welded to 4.5 BS I am not sure though. The ones I bought from NPD are nice and fit well on my 68 with 10 bolt nova 8.5 rearend and rear disc brakes

^^^ Ya -- what he said.

I had vette 15x8's on my '69 (4" BS) The fronts "looked cool" but would rub the fender unless I ran tall front springs. On the rear, I trimmed the inner w/w lip a bit and they JUST cleared. I'd guess on a '67 they'd barely fit on the rear with "stock" height springs.

To my knowledge, there are no 15x8" factory rallys w/ 4.5" BS. I think NPD sells the Wheel Vintiques repros that are avail w/ 4.5" BS (and maybe 4.25" as well?).