This was cleaned as is pictured.. has casting number "1" 1971 and 1972 without A/C and 342 gears Standard Cooling Waterpump with cast iron impeller $165 shipped to lower 48 states Consider to be CORE for rebuild

 

 

What is the shaft length? Looking for a 5.072"

 

This is the shorter NOT heavy duty cooling pump measures 5inches to flange....For 71 and 72

 

Here's my dilemma in this thread:

https://classicoldsmobile.com/forums...g-over-191894/

I don't know why my 5.6" water pump is positioning the fan so deep into the shroud. Water pump pulley incorrect?

 

The water pump pulley will change BELT Alignment not how far fan goes into the shroud....

The original cast iron impeller works better than the "tin star" commonly found on rebuilt and replacement pumps
a replacement fan clutch may be Longer than the original , fan further from pump..
5,6 water pump is 1/2 inch different than original non air , fan further from pump...

When I run racing fuel in my 1972 110 octane in my 1972 gauge reads 20degrees cooler... than pump gas

 

Brian is completely correct on this.