Have what I think is a fuel problem in my 37 T20. Tore the carb apart to clean it and I happened to have some carb parts from my 38 parts machine nearby. For some reason I noticed the venturi's looked to have different sized openings. Sure enough, the carb venturi I was running has about a .010 bigger throat than the other. Makes me wonder which one is correct. Anybody know if there is a venturi dimension difference between a K5 on an F20, T20, and F30? If I do happen to somehow have an F30 venturi would there be any benefit to running it in my carb since I have the engine bored to 4"? A