I'm Not Sure About "Normal", but ...
... I just went through changing my mixing elbow and my typical cruising temperature (at approx 2,500 RPM) went from just under the 150 degree mark to just above the 100 degree mark. I have no idea if the temperature gauge is accurate, but the change after replacing the mixing elbow was noticeable. I'd be interested in hearing more opinions on this as well. Thanks, Gary