Oil Pump Difference

[Copyman]

I have 97 E-350 7.3 that I am rebuilding and order new oil pump but the new one and the old pump are different. The Old pump inner gerotor has 14 teeth the new pump inner gerotor only has 10 teeth on it. The old gerotor is 1 3/8" thick and the new one is only 7/8" thick. I took it back to Napa and they call local dealership and the parts guy counted the teeth on the one they had and said it only had 10. Does anyone know what the difference will make. I'm kinda stumped about wiether to put the new one on or try and find a different one. Any help or insightwould be greatly appriecated.

[Cablifter]

Make sure they are not giving you a pump from a 6.0.