I'm not so sure you would even need to run a check valve off the pump. I realize for competition they require a 3 way dump valve, but for a daily driver, I'm thinking you might be able to do without. If the waterman .500 is rated at 4.90 GPM @ 4000 rpms, then at 3K RPMs in our trucks, it would only be turning 1500 RPMs which in my calculations would be moving about 1.83 GPM. This is on a Sprint .500......A sprint .300 @ 4000 RPMs is rated at 2.8 GPM, at 3K RPMs in out trucks, it would be turning 1500 RPMs and would be moving 1.05 GPM.....not a significant enough amount of flow to warrant check valves, and could be used with a stock OFV off the P pump I would think. Someone let me know here if I am calculating this wrong. I can understand if a sled puller was turning 5K Rpms, but for a hot street truck, I'm not seeing the need for the complicated plumbing. If I'm completely wrong, please school me.....lol