I have a 1954 Chevy 261 ci with a Model B Rochester carburetor. This carburetor has TWO holes in the throttle body where it mates to the insulating block to the manifold. One hole is perpendicular to the face and the other is at a slant. I also have a slightly older Model B carburetor and a slightly newer one. One of these other carburetors has one of the holes (at a slant) and the other has the other hole (perpendicular to the surface), but neither has both holes. (One of the holes might have been to operate a governor.)
I need to rebuild the two-hole carburetor. I got a kit from NAPA. It was the only one they said they listed. But then I read the ‘54 shop manual. The shop manual says that there are two different carburetors and, “The differences between carburetors are the sizes of the carburetor throat diameters and some of the jet orifices.”
So, before I open the kit and use it, will I be putting the wrong size jets/orifices, etc. (for a 235) into a carburetor designed for a 261? The NAPA people don’t know the answer. Also, how do I tell whether to allow one of the two holes to be blocked by the gasket and if so, which one?
This looks like a potential source of future mysterious symptoms that no one could then diagnose. On the other hand, it could be that none of the crucial different-sized parts are in the kit and the hole problem is not a real one and I shouldn’t worry.
Any help will be most appreciated. If there are indeed people who sell a kit for the 261 version I sure would like to get and use that. The rest of this engine deserves to have a nice carburetor.
