My old v6 (198) used to run at about 180 degrees, I have recently stepped up to a 225 v6 and it wants to idle at about 200 degrees. The only other difference is that on the old moter the temp sender was up front by the water pump and on this new moter I had to put it on the back of the moter ( it actually screws into the back of the intake manifold). So the question is what temp should these run at and what is too hot. I was told that the odd fire engines ran a little hotter then standard ones is this true. If it helps this moter came out of a 69 commando.