I'd go with one of these..
TR6060 with Standard gear ratio (Rated at 850Ft Pounds)
1st: 2.97
2nd: 1.78
3rd: 1.30
4th: 1.00
5th: 0.80
6th: 0.63
TR6060 (Option 5th and 6th- 0.74 and 0.50)
1st: 2.97
2nd: 2.07
3rd: 1.43
4th: 1.10
5th: 0.84
6th: 0.63
are you going to be upping the HP ??