FWC or RWC? I don't have psi guages, so i couldn't speak to that. However, I would guess that the higher number would be correct. Overheating issues are caused by blockages which restrict water flow and reduce the cooling. I've never heard of someone with too much water flow. Even in FWC engines, calcium and junk can build up in the heat exchanger. Typically, even in FWC, the engine is closed cooling, but the mainfolds and risers are raw water cooled. My fuel pump is raw water cooled as well. blockages in the manifolds and risers are also pretty common. What are the temps on both engines?