I am thinking about putting 18"x8" wheels on my '91 Camaro. Does anyone have any pictures of this or a similar size? Also, how large of a tire can I fit on that without any custom work?

 

I'd say a 245 or maybe a 255 tire on a 8" wheel.

 

How big of a sidewall though?

 

26" tall tire is generally what you shoot for. Leaves you room for lowering.

 

I agree with Shifty in that 26" would probably be what I'd shoot for, knowing you'll almost never quite hit the number dead on. In this case, a 245/40/18 is 25.7, which is the same as stock, and a 245/45 jumps to 26.7. Definitely run the 245/40 at 25.7"