you can NOT put that wide of a tire on an 8 inch rim. no way! i have also not yet seen a single car with tires that wide, no matter what rims were used.
uhhhh, the stock rims will only safely hold a 255. on the front, 10 inch rims with a 285 is the widest I've seen, and the rear I've seen an 11.5" rim, but the widest tire so far is a 325. I hope to do a 345 on the rear with a 12" wheel, if I can win a lotto or something to pay for the wheels.