Common sizes would be a 18x8 w/ 245/40/18 or 18x9 with a 275/35/18 front and a 18x10 with up to a 305 in the rear depending on what you have done with your exhaust. We have setup up a ton of the A-bodies with sizing ranging from 15-20's, it all comes down to the look you are after. Check out the gallery on our website
www.driverzinc.com for some different ideas.