Hi, is the main difference between 5.1, 5.6 and 6.0" water pump only the location of the fan vs radiator/shroud or the location and flow of water pump ?

Thanks

 

I believe the necks are different depending on the car options. Ac, motorhome etc. I learned the hard way. Ultimately I took the job of water pump to a local parts store and they figured out which one I needed.

 

Differences in inlet diameter are a function of model year (70-earlier vs 71-later). Impeller differences are a function of application (A/C vs non-A/C). Length is a function of the application and is NOT directly related to A/C or not. For example, my 67 Delta uses a 5.1" pump for A/C and non-A/C application. The factory had two different P/Ns, but the aftermarket replacements are the same for both applications.

 

Thanks Joe, interesting as always