dont waste your money if its a cub,builders will just feed you alot of bs,and in the end you will end up with a clean up port job anyway
lighter frame,pipes,domes,timing,and gearing will gave way more than leeting someone grind on your cylinder....theres storys i could tell you about BIG TIME engine builders whos ported cylinder and gave me domes to go with them and bikes was no faster than what i could do myself.