245-60 is as wide as you can go as far as I know. Only offered by BFG, unless someone else has found otherwise? That's what I'm putting on the rear of my '71 Demon w/ its original sbp 14" ralleyes. I think I'm going w/ a 215-70 up front.
235-60 is pretty common.
Agree 245 60s Have on my 72 Scamp with rallyes- 7 1/4 stock rear No clearance problems may be room for 255s....