better mileage, less lag, more power, lower egt's. why run the lifter killing stock cam in a reman engine is the question? the colt stg 2 is similar to the stg 1 except that it is not a regrind, think of the stg 1 & 2's from colt as a RV cam for the gassers. I think that some other vendors stg2 is more of a performance cam. So I guess the anwer to the original posters question is it depends on whos cam you plan on running. most guys today are getting there "stg 2" from colt. and according to colt its safe to run with stock valve train. if you are running elites stg 2 cam I don't think its recommended. But best bet is to call the manufacturer.