The T-bike cams perform about the same as the 790 cams. As stated above, the 813's do a little better.
As a general rule, I understand that TPUSA does not release the grind spec to those who don't buy the cams. Why? I have my theory, but you need to ask them.
Better cams are necessary for 865's (& 865 based BB's) in order to make the most out of the motor; with 790's, the OEm cams are already good.
What I can tell you with certainty is that I have no regrets with the 813's & would do it again without hesitation.
