going by my jackshaft rpm chart stock gear is 23top/39bottom w/70 pitch chain, at 8000 rpm(this is engine operating RPM) Miles per hour is 101.3mph, if you change the top gear to 23 and bottom to 43 and chain to 72 pitch, you will achieve 91.9mph, there is all different kinds of combinations possible, You just have to make sure they will work w/your chain case, (this info came out of a 2002 polaris service manual)