Hello John,
I would have to measure my Good Year Eagle II's but, I'm in the process of changing to the Billboards and their supposed to be like, 26.5" all the way around. I now believe I have 370 gears not, 331's. Currie does not even have that selection. The previous owner told me the rear end had 331 gears.
With the Eagle II's and my Tremec 3550 trans, at 60 mph I'm right at 2,000 rpm's. That's really nice. With my KC alum. 482 and apx. 600-650 HP/TQ and hopefully the TKO 600, I would be curious as to the rpm and the Billboards with the 64. or the .82 overdrive ?
I would appreciate your time.