What are the safest size 18 inch drag radials I can put on the rear of my Camaro. I bought it used and don't know the backspace ing of the wheels. Would like to get the widest I can. I have gone with 315/35/17 on other cars but never tried with the 18s

 

Tough to say when you don't know the backspacing. But on a 10" or 10.5" (I don't even know) c5 z06 wheel I ran 305/35-18 ET street IIs
minor BFH mod no fender rolling.