In other posts, I have listed carburetors designed to be used on Chevrolet engines by both Carter and Stromberg.
Here is a list of the carbs Zenith sold specifically for Chevrolet 216 engines, some of which were sold for use on Chevrolet, others for use on G.M.C. trucks with Chevrolet 216 engines:
Updraft (C.O.E. pre-WWII):
9766
Downdraft 1938-1942:
8686
8821
9038
9042
9060
9293
9913
9947
10355
Downdraft post WWII (FLEET ONLY):
10469
Zenith did not specifically list carburetors for the 235 or the 261.
Zenith did list a number of "universal" carburetors, in varying throttle body, and venturii sizes, and adjustable main metering jets. These normally were listed in 20 CID increments (i.e. 200-219, 220-240, etc,). These can be made to work (gasoline engines are very forgiving), but NEVER as well as one specifically calibrated for a specific engine (assuming one has a basically stock engine, once modified, the owner becomes the "engineer", and is responsible for how well he/she did their homework). Not going to go over these, as there are literally dozens; and would not be my first choice.
I have no record that either Autolite (Motorcraft) or Holley made carbs for Chevrolet inline sixes (well, Holley did make one in 1922~1923).
So now there are lists for: Carter, Stromberg, and Zenith. I will leave the Rochester B's list to someone who thinks more of them than do I.
Jon