[rdorman]

Fixit is right, what have you done so far? Also, the 351M to 351W caught my eye. Roscoe (another member here) recently had an issue where he had a 351C or M pump on a 351W. Maybe you have the reverse.

Do a search here on overheating problems if you are not sure where to begin in diagnosing the problem. Lots of information available.

Rick