It's all a question of ratios.
I'm running a T56 6 speed in mine and I think the ratio set in the first 3 gears is better than the TKO or TR3550.
1st gear in the the 5 speeds is way too low and there is a sizeable gap between 1st 2nd and 3rd. The T56 has a tall 1st gear @2.66 and a taller 2nd and 3rd gear as well. The actual spread from 1st to 5th is much the same as 1st to 4th in the 5 speed. With the right final drive ratio you have a close ratio 5 speed with an excellent OD 6th for economy.
Here is a comparison of the ratios for the TR3550 and T56
TR3550---------T56
1st--3.27-------2.66
2nd--1.98------1.78
3rd--1.34-------1.3
4th--1.00-------1.00
5th--0.68-------0.74
-------------------0.50
I'm running 3.9 gears in the rear of my classic and I think this combo should work well.
here are the speeds thru the gears for my setup:
1st @ 6K RPM is 71 KM/H
2nd @ 6K RPM is 106 KM/H
3rd @ 6K RPM is 146 KM/H
4th @ 6K RPM is 189 KM/H
5th @ 6K RPM is 256 KM/H
6th @ 6K RPM is Just silly.
However 6th @ 110 KM/H is a comfortable mile eating but not gas guzzling 1745 RPM. And still close enough to the power that it'll pull away easily for passing on the freeway.
Check out all the ratios at TTCs web page:
Transmission Technologies
I'll try to stick some TR3550 ratos into a spread sheet as well.
Cheers