Nothing and I agree with you. Been running and racing with an Isky .680-.660 276-281 roller for longer than I can remember but it has nice street/strip lobes which are easy on valve springs only needing to change em twice but still run 9's or low 6's 'no problem and is tame as a kitten till you hammer the loud peddle. And now with a t-ram it's actually more docile and sounds like I lost a bit of duration so the big thing is lobe design no doubt and checking/setting lash a few times a year......Go for it....