Went to NAPA to try to buy a water pump for the 1956 235" in my 49 half ton. This pump has an external impeller which goes into a large hole in the block.
NAPA has photos on their web site of the pumps which helps greatly.
The pump which fits later model 235" with the external impeller (like mine) has a 5.25 inch shaft, measured from the mounting surface to the hub.
The other pumps which have the impeller intenal and covered with a flat plate measure 4.125".
I ordered the former but when I measured my shaft length it was much less than 5.25". Therefore there must be another pump available like mine but with a shorter shaft. I do not think mine was modified because it was done more than 12 years ago and I wonder if they even modified them back then.
