As previously noted by others the 964s was designed for the 216; not the 235.
This is a classic example of why more than one carburetor is produced; and why carburetor selection is so important.
The main venturi in the 964s is 1 1/4 inch. The main venturi in the 967s (for use on a 235) is 1 5/16 inch. Does this 1/16 of an inch really make that much difference? YOU BET!
Do the math:
The overall venturi area of the 964s is 1.227 inch while the overall venturi area of the 967s is 1.353 inch. So the overall venturi area is 10.2 percent greater on the 967s. Now factor in that the booster is the same on both so the percentage increase is probably more like 15 percent.
A 235 is a little more than 8 percent larger in displacement than a 216.
This carb should run well at idle and very low RPM (giving increased low end efficiency due to higher air velocity) but will run out of steam prior to the normal maximum RPM of the engine; and produce significantly less power under load (slowing down on hills).
This was a concept developed in the 1930's for use on taxis. Run a smaller venturi for a vehicle that would normally run 25~35 MPH maximum, but increase the fuel economy at the lower speeds.
You are running out of air!
Jon.
Last edited by carbking; 08/28/2009 12:30 AM.
