I called Fuel Customs about this intake because I wanted to know if it was designed to fit the stock or aftermarket carb. Most of us use a 38mm or 39mm aftermarket carb, which have a larger intake bell than the stock 34mm carb. Anyway, he said he designed it for the stock carb. He gave me the diameter--which I think was in the 50mm range--but it was smaller than my 62mm intake bell. So, I don't think it will work with larger aftermarket carbs.