Damn noisy horseless carriages!
Modern engines are only as powerful, economical and tractable as they generally are because of EFI. Sure you could fit a carby in place of the EFI system, but that would be a backward step IMHO. Better to fix the problems you have, rather than replacing them with a whole new set. Get yourself the equipment necessary to work with what you have and study up on how to use it. It's daunting, but not insurmountable, and very satisfying when you conquer it.