I was concerned about using the pollak valves from NAPA because how much they can flow, the plastic body and by the failures reported. I contacted and purchased this one from Parker. It is a marine valve and there is no plastic on the body. Additionally, it'll flow 300 gal at less than 3psi. I installed one and it works flawlessly. However, they invoiced and shipped me two by mistake and I have this one for sale for $375 + shipping. The fittings are not included.
Best,
Ron