Here are the trade-offs:
Short-shaft 1955-2nd to 1963 water pump on a 1955-2nd to 1963 235/261 block in a 1947-1955 Advance-Design truck:
- might be more efficient water pump in terms of cooling (questionable)
- the fan is 3" lower relative to the radiator, resulting in less efficient cooling
- a fan blade must be found that will not interfere with the harmonic balancer
- possible fan-pulley and/or harmonica balancer and/or generator-pulley miss-match in diameter and groove widths, depending on the equipment/pulleys that will be used. This is not just a fitment consideration, there are implications related to fan RPM.
Pre-1955-2nd 216/235 water pump on a 1955-2nd to 1963 235/261 block installed in a 1947-1955 Advance-Design truck:
- might be less efficient water pump in terms of cooling (questionable)
- fan is in the correct location relative to the radiator, resulting in more efficient cooling.
- allows use of the truck's original equipment harmonic balancer, fan pulley, and generator and the original fan belt will work fine. No fitment problems and original fan RPM.
There is also the consideration of almost original appearance when using the water-pump relocation plate (made and sold by Pre '68 Dave).
