Sorry, OFF TOPIC! But bdog, my dad was thinking of shoving a carbed 306 into his 2000 V6 stang, but we are worried about passing inspection. How does that work with yours?
And back on topic. 315s are the widest you should go if you dont want potential rubbing issues. But you need new rims...so 275s (which you probably have) are about the biggest you can get. (315s should fit on the Y2Ks but it probably wont look very good.