[Adrian Worman]

This will sound very lazy, but I never connected my heater hoses to the water pump and when I went to do it this evening while doing some little jobs, I only found one hose spigot still in the pump housing, the 2 other possible locations have a 3/4" plug in one and another water temp sender(3/8") in the other. The little 1/8" temp sender is there as well. I'm a little confused

[dave-r]

The one in the 3/8NPT hole will be a thermostat control for an electric fan.

[Adrian Worman]

But that only leaves the 3/4" one to put a hose tail into and thats too big. Where would the primary for the heater matrix have come from otherwise? The small hose tail thats installed looks like it does the return.
I will check out the 440 in the motorhome at work

[Adrian Worman]

Well the motorhome engine has left me just as unsure as before, the housing is different, I'm sure there were a few different castings, but by the looks of it I can use any of the available tappings and it should'nt make any difference. I was only worried about the effects on circulation if I used 2 ports that went to the same part of the pump housing. The main reason to reconnect it in the first place was to get a little more capacity into the system and to relieve some of the engine temp thru the heater hoses and matrix