Tom, I removed my "T" fitting and relief valve and plugged my through hull to see what would happen running just the sea strainer. My pressure is now usually around 30-35, rarely over 35. This pressure should be fine with closed cooling. Just the resistance of the sea strainer and not having the water rammed directly from the shorty to the pump reduced the pressure considerably. Now I have an extra through hull on the boat
. Just another option for you to think about. I might sell the "T" and relief valve if you are interested.