Chevelle running hot

[70SS454]

Radiator is not original and I had it checked out. The shop said it was good to go.
The Hayden clutch that I installed was the one that was suggested (heavy duty). It sounds like it is even on on the highway on a cool day. I hear it over the motor. I don't think it ever kicks off. I need to idle the motor from cold to warm on the drive and pay specific attention to it.
The mixture is already pretty rich. You can smell the richness in the exhaust. I also had the mixture looked at by a local hot rod shop and they said its where it should be.
I am not sure if the gauge is correct. I will look into the infra red thermometer. What part of the engine do you shoot it at? I drove it again yesterday. Outside air temp was 60*. When I was moving, temp sat at 210*. After idling for a min or so, it still jumps to 230 and then drops as soon as the car moves.
Ya know, that just made me think....at night, at idle my lights are dimmer than if the rpm's come up slightly. I wonder if that voltage drop at idle could be affecting the temp gauge? Causing the reading to change at idle. I think that's prob not it but I still wonder.