New to site have what appears to be a old margay chassis 70;s 5hp tecumseh hegar quick chage sprockcet, never have changed it was told it had at one time a kt 100 motor attached single airheart disc brake good little kart son who is now 18 had lots of fun starting about age 8 on it have asphalt tires and a set of douglass and burris dirt tires for it What i need is a gearing starting point for a 1/5 mile dirt track