Wheel Fitment Questions

I am interested in getting aftermarket wheels for my 82 z28. I’ve been told many different things but i think it is a 4.75" bolt pattern with 4.5" backspacing. I have found 2 different types of crager wheels I want to put on my car but both have a little more less backspacing or offset. I was wondering what spacing I can get away with. I don’t know how to measure backspacing or offset or what that will do to the wheel and I don’t want it to interfere with the brakes or look funny. I was also wondering if anyone knew the thread size for the lug nuts. I know that is a lot to ask but im going up to summit to get the wheels this weekend. Thanks a lot Chris.

here are a couple links to the wheels im interested in. Will they fit?

The crager SS
http://store.summitracing.com/partdetail.asp?autofilter=1&part=CRR%2D61715&N=4294923107+4294923106+4294923105+4294793325+4294 906456+
4294906455+115&autoview=sku

The crager star wheel
http://store.summitracing.com/partdetail.asp?autofilter=1&part=CRR%2D3415736&N=4294923107+4294923106+400292+4294923105+42947933 25+4294906455+4294795102+4294795045+115&autoview=sku

WE have a "Wheels and Tires" forum.... I'll move the post over there for you.

Acording to Skulte Designs:

Camaro 82-92: 16x8 front, offset = 0mm, backspace = 4.35"
Camaro 89-92: 16x8 rear, offset = 16mm, backspace = 5.00"

I don't know much about the 3rd Gen wheels, so the above reference is the best I can do. Increasing the "backspace" moves the wheel deeper into the wheel well. That can cause interferences with brakes, suspension components and the body if you move them in too far. Reducing the backspace moves the wheels outwards, toward the edges of the fender. Move it out too far, and you can rub on the fender lip or even end up with the wheel outside the fender.

There is an FAQ at the top of the "Wheels and Tires" forum. There is a writeup in there on how to measure offset, backspace, etc. There's a small diagram linked from Tire Rack showing the measurements. There is also some good info on this page:

http://www.skulte.com/adapterfaq.html