guessing you sprocket is #35 chain and that youl get about 12" tires a 12tooth #35 chain cent clutch with 3/4" bore is the ticket, unfortunatly with a cent clutch you sort of stuck in the 1 to 6 gear rateo range. if your realy intersested in boosting preformance i wound suggest a torque converter but at about 180 bucks you may not be intersted. another way to boost preformance is takeing out the gov but that would be for some one whos taken a part an engine a few times