3.23 to 3.55?

The tires are 255/60/15's (27.1"). I put a 72 340 in it. It is modified to 10.5 to 1 compression, 2.02 valves, air gap, headers, 650 carb, probably around 400 hp. It is a dog out of the hole, but is scary fast once the rpm's are up.

With 27” tires I would opt for 3.73 gears if you are buying a new set of gears, 26” tires & the 3.55 would be fine.