I've got GEN V 454's running on the standard belt driven pumps. I did buy new pump assembly's a few years ago from Dennis Moore but I don't know the GPH they deliver. I sent him an email but never heard back. I don't remember if I bought OEM or maybe upgraded. The "in and out" fittings have 1/4" bores. I removed one of the fittings from the pump and the physical threaded opening in the pump is 1/2". I suppose I would try to locate fittings that had larger internal bore's. My questions are, does anyone know the GPH of a stock pump and the second question is if these are stock pumps will they support 500hp? Thanks for your help.

It should as that is the same style pump that came on my stock HP500

Perfect. Thanks