Calling all 351W guys-Please help identify which water pump I have

[Stang_ROTY]

I am having problems with the car overheating and pushing water back out through the radiator after about 2 minutes of idling. I am using what I hope is a 302 5.0 water pump on a '69 block. I's supposed to be reverse rotation. the part number for a standard rotation is 8843 and the reverse rotation is 8840. The reverse rotation is for a serpentine setup which I am using. How can I check to make sure my water pump is a reverse rotation and not that standard. I'm thinking maybe Summit sent me the wrong pump. It's either that or the pulley'a and/or thermostat, right?

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Finally DONE!!
93 GT, 393 stroker w/ Edlebrock Performer heads and EFI, 30lb injectors, Dynamic Roller Mite C4, 8 pt cage, Sothside Machine bars & Sub-frames, 3.73's, '69 351W block w/SCAT crank.