this is my go kart that i am restoring. when i finally found it behind my brothers friends shed it was rusted and didn't have a engine and front wheels. then i bought a 6.5 hp engine from harbor freight. polished the wheels and sanded the frame. moved over the platform that holds the engine. painted it. fixed the gas pedal and throttle cable. made a seat. and made a ram air intake. all i need now is new wheels a centrifugal clutch and chain. about a year ago this was very fast with a 3hp engine and now that i have a 6.5 it will be alot faster and stronger. right now i have a 60 tooth sprocket and was wondering if it would be fast enough. should i get get a 40 tooth?