Interesting reading....

I put a new 440Source pump & Housing on my 600 HP 440 in my Daily Driver '68 RR last year because I am cheap LOL Never really spent too much time looking @ either piece... only issue I ran into is the pump impeller is VERY tight to the housing, so tight that with no gasket they touch... the thickness of the water pump gasket IS the clearance between the impeller & the housing...

Have to say this motor probably runs cooler than any I've ever built. 160 T stat & it will sit on 160-165 on any "normal day" I just drive it 120+ miles to track & back couple weeks ago on a 94 degree Saturday... Climbing 7 mountains here in PA on 322 (very long very gruelling mountain climb) I never saw over 174 degrees. This is alum head (INDY EZ's) with killer big Alum rad & high flow mechanical fan...

It will climb to about 180 if you sit @ stop light for 2-3 minutes in high heat day.. so the low speed flow is not worlds greatest, as some have mentioned. If I was really concerned about that I'd put an electric pump on it, which has constant flow rate... as soon as you start moving again & RPM's come up above 2000, temp comes right back down into the 160's. If you are really concerned about high temps sitting @ a light or in heavy traffic, pop it into neutral or push in clutch & rev motor a few times, helps circulate water, & will keep temps lower...