I know what ended up working for ME. I used a 160 high flow Stweart thermostat, at @yellow rose's suggestion. I generally don't endorse a 160, but in my situation, running really high cylinder pressure and detonation prone, I did it. Never gets past about the 1/8 way mark on the gauge. I did it trying to cool things down to get rid of detonation issues on pump gas.....and it worked, along with everything else I did. You may not benefit from a 160, but I certainly do recommend a high flow one.
