There off an '87 with a 5.0. 16x8 front and rear. front has 4 1/2" backspacing, rear has 5". They look like several other pontiac rims but the center is out further than the outer edge, there is an outer lip of about an inch, my friend says on the formula rims the center is in futher and angles outward to the outer edge. Thanks for info if you can make sense of this, if I had a camera I'd post a picture.

 

Sounds like it. You will have to cut+paste this link, but its a pic of the rims used on 87 Formulas.

http://www.geocities.com/madmax0/newpics/Rims.jpg

 

That's them, thanks for the quick response.