Old Faithful??

For what it is worth I have never seen a water pump cause a overheating problem with out seeing something major wrong with it when I pulled it off. ie Ford contour where impeller cracks and spins on shaft or some Taurus and Tempos where the coolant was so bad it rusted off the impellers. I have seen lots of thermostats in backward or bent. Also saw a lot in the housing crooked on 289 and 302.

2nd pump... I put the new pump on and left the T-stat out.... I am guessing it was a bad pump... I put the stock pump on it (the part number it called for) I never changed timing covers if thats what you were meaning... I won't know if the T-stat was the problem untill I put it back in... But since it's working now, I don't see a reason to mess with it...

Did you see a loose impeller or blocked ports from too much sealer?

Nope sure didn't.... I am starting to think the impeller on the "old" New water pump was pressed on backwards. It was a reman and not a new pump.... without seeing the other pumps impeller, I can't be sure...

If you have the new/old pump just examine the rotation of the impeller. You should be able to tell. The pump turns clockwise.