Joe was using 33x10.5Wx 15 M/T, on a 14" wheel, in Vegas, and he made it to the semi's running 7.06 to 7.07 in B/ED, running a 3 speed trans.
I have run the same tire, but on 12" wide wheel [JrFuel rules], and so far ran a 1.01 sixty foot time. I will try some other combinations with the M/T like higher launch RPM, and different tire pressure. I ran 7 1/4 to 6 3/4, but Joe found the best is 6 #. Down side on the M/T is they are heavy, rotating weight, like 34 lbs, where as the GY 31x12x15 weight 26 lbs, and our JF car ran 7.06, 7.07, 7.08 at the CHRR, running a 2 speed trans.
I hope that helps.