Finally got the boat in the water today after a long long engine building process. One motor ran perfect. The other had super high water pressure... Everything between the 2 motors are the same. Dart mills but basically HP500's. Stock water pumps, crossover to Procharger Innercooler. Then dumped over board after the cooler. At 3500 rpm one motor has 15psi water the other the gauge is pegged, way past 30 psi. Holy Crap! shut down, but too late I got yet another milk shake. I have not tore into it, but I know at 30+ psi h20, I am missing some of my intake gasket. Everything is plumbed the same between the motors. Has anyone else experienced this high of water pressure with stock style HP500 pumps???

what are you using to read H20 PSI? mechanical sender and gauge or smartcraft/digital?

Mechanical. The water out the cooler is clearly under more pressure than the other. I pulled the intake today and no gasket pieces missing but it was not stuck either. I un bolted it and the intake lifter rite up. I have never had one come off that easy. I think it was pushing water everywhere.

have you trashed a water pump impeller recently,if rubber from it gets stuck somewhear in the exhaust system,it can cause resistance,that can increase water pressure.

I think I found the issue. When experimenting with the old motors, I drilled some holes in a few t-stats. I had one in this motor with 3 1/8th in holes. I think the stat was not opening an thus pressure was higher. Flushed everything, new intake gaskets and a punched out stat was the order tonight. Ran it a short period, much lower water pressure.