Correct, it all depends on the ride height.As a couple people said, 325/50's can be made to "fit" with a BFH, but the tire will be sitting under the wheel lip and the ride height has to remain quite high in the rear to prevent rubbing.
Thanks for the info.the rear end is a 9inch, narrowed 1inch on each side 52" backingplate to backing plate and the wheels are 6" bs, but I have a 1/2 in billet spacer on each side to move them out (they were rubbing the frame rails, not the stock tubs. My draglites are 5.5" bs and they fit perfectly. Wilwood drag brakes. With stock width and disc brakes, 6.5 would fit the same.