My 1850 gas is running on the hot side and after checking the obvious, I want to change out the thermostat to rule that out. I read somewhere about an improvement for this application, where the thermostat had a spacer that went along with it? Can anybody give me any insight on this?

The Agco one seems pricey- $70 or so. I checked the Stant website and they make one for this application as wel and it was about half the price. Maybe I can go that route instead?