a comet torque converter woold be a good adition but a bit expensive. to woold give you better top and bottom end. and as far as the engine you coold shave the head doun for more compression and port the block. both coold be done at home but if you dont know what you are doing its better to have a kart shop do it. porting can be triky. whatever you do, dont pull the govenor on that engine, there are no parts avalable to make that safe.