Chev's of the 40' may or may not be confusing. I do not know what each of these pumps is for and which to use, if any, to solve the issues herein.
They both say they are for the same motor and same trucks. They both say Cars and Trucks. One is called "short", the other called "conversion" ?????? One says use a certain fan they don't sell???? One of the pumps is not available but they are taking names. So sit on your hands and on your project and wait? What a goofy site IMO. If anyone ever asked me if I would buy anything from them, I would say no. There are several other vendors with this pump.

Regarding this "motor/pump swap issue" and what to do, J. Carter makes more sense to me. The Stovebolt advice makes more sense to me.

Here are the Co40's pump descriptions:

3741033 29+54
CHEVROLET Water Pump - Short Shaft W/ Cast Iron Pulley, 1955 & Later 235ci, 261ci 6 Cylinder With A 3/8 Wide Pulley ($100 Core)

This is a water pump with a short (narrow) pulley and shaft (Cast Iron). For use on 1955 & later 235ci & 261ci engines. Includes gasket. This has a 3/8" wide pulley.

For 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 Chevrolet Cars and Trucks




3741033LP 37-54
CHEVROLET Water Pump - For Conversion To 235.???? Includes Gasket For 55 & Later 235ci & 261ci 6-Cylinder (No Core Charge)

This is a water pump for conversion to 235ci.???? Includes gasket for '55 & later 235ci & 261ci 6-cylinders. *Must use a newer 235ci mechanical fan (not our part #838277 37-54&quo...

For 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 Chevrolet Cars and Trucks



Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn