Ok, here's the deal. I just installed a new crate engine and during the break-in the temps got up to about 220. Kind of high, but not unheard of for a tight new engine. I have the original dash temp gauge and a new sender in the driver's side head. They changed the size of the hole and threading in the head on these new crate engines, so I had to get a brass bushing to adapt it, but no problems there.

Well, I put in a new GM thermostat that I tested in hot water, so I know it opens fine. I didn't have a temp gague in the pan of hot water, but it opened well before the water started to boil, so I am taking it that the 195 degree stamped on it is at least somewhat accurate.

Ok, help me interpret what I'm seeing here. I do remember that the old engine used to hit about 220 before the temp would drop and it would stay below the 220 range in normal driving. The new engine and sensor do run up to just on the high side of 220 and I notice the temp drop back. My thinking is that I'm seeing the effect of the thermostat opening at it's rated 195 design temperature.

Ok, I am guessing that this is telling me that my gague is inaccurate and the 220 I'm seeing on the gauge is actually closer to 195 degrees as that is where I notice the temp drop when the thermostat opens. Am I right on this? If so, I will not get bent out of shape while driving around town and the temp is at 220 or a bit higher as this means I'm really at something like 200 degrees and should be in the safe zone. Am I interpreting this right or am I mixed up?

I am seriously considering putting in all new Autometer gauges in this thing and making a custom panel for the dash in the future. Anyone else notice temp gauge inaccuracies on their ride?
Thanks for any input or observations.
Brad