it won't be a 1 barrel, if it is you've got a strange manifold or adapter - check your local parts store, I don't have the number on hand, just a small check valve that restricts the flow to the carb and prevents any possibility of losing vacuum or reversing flow .... the factory replacement for the draft tube looks about the same but had a fitting to accept the hose shown in my pic, only about 1/4 or 3/8 ID .... if you don't have a shop manual,
see the 55 manual here, similar valve and setup
Bill
