tires
 

on a forth gen trans am what is the stock tire size and how wide of a tire can i go before i get rubbing.

There should be a tire placard (sticker) on the car telling you the stock size tire (although I am sure someone will chime in soon)

mine are 245/50/16

my 2002 is 275 /40/17's

firebirds can take more meat in the rear (that sounds really gay) than camaros due to the fender bulges. ive got 285's in the back on a 9.5 rim. yes stock size is 245/50/16 and the factory plus one size is 275/40/17.

The stock size is 245/50/16 for plain Z28's and Firebirds. The SS and WS6 cars have the 275/40/17 on 17x9.5 wheels. You can run 315/35/17 on 17x11 wheels on the rear but you most likely have to trim the bumpstops like I did and you might need to center the rear with an adjustable panhard bar or hammer in the inner fender if it rubs a little. I just needed to trim the bumpstops and my 315's fit fine.

:rofl::rofl::rofl::rofl::rofl::rofl::rofl:

I was able to put 315-35ZR17 Nitto Drags on the back of my SS with only a 9.5 wheel, and no beating the fender.