[GuyBFF]

Hmmm, the Ford rad you have is about the same core as Big Momma and the same as the one JimS and me are using. I really don't think an aquacube will improve anything if this core is in decent shape (really this should be your best solution).

It interests me that you saw a difference in the cooling temperature by switching the hoses. Heater cores are usually used with the inlet in top and the outlet at bottom with the intent that hot water will rise a bit more than the cold and get cooled a little more (this is what they tell you in auto parts, but I didn't think there'd be any difference in computer cooling).

Maybe try turning and tapping the core to make sure theres no air-locks in it. Also is this a new core? If not maybe use a auto rad flush chemical (out of your computer, don't run it threw the pump). Also you could try situating fans to suck rather than blow. Can't think of much else.