I have gotten a few different opinions. So I say to the group......... Thermostat or no thermostat. It's for my BBC. I found out that the plumbing is not right. This has been I hope the answer to the problem of water in the oil. Bought a new Bassett T and am getting ready to put it back together. Take the thermo housing off to check it out and it's gutted. It's a 4 port thermostat. Should I put a thermo or not. Should I just try it and then see what happens? HELP!!