yeah i agree with radials. i have 20/65/15 in the front (i have discs as well) and 265/60/25 in the rear, but the rears i had to install billet 2" bolton spacers but man the look is awesome and fit the wells with no issues and now miss the stock shocks and the bed. i do have a 70's caprice 10 bolt in the rear though. not sure if it matches the dimensions of the stock rear if you have stock.
again it looks awesome!