"The TR3550 and the TKO have the same ratios but the new TR3550-II and the TKO-II have different 5th speed ratios. Below I will list the ratios. If you have any questios call the TTC/Tremec tec line at 800-401-9866 or visit our web site.
TR3550/TKO TR3550-II/TKO-II
1) 3.27 3.27
2) 1.98 1.98
3) 1.34 1.34
4) 1.00 1.00
5) .68 .82
Rev) 3.00 3.00
: : They are the same trans except the TKO has a larger input shaft."
Found the info on a BB
also helpful ...click on tremec once in the link page
Tremec etc
One more real good link answers most of your questions
Fortes link