so when I turn the ignition on, the temp gauge snaps to the minimum value just like it should. When I turn the key to start it, the gauge snaps high so hard that it gets stuck, and I have to open the dash up to un-stick it. I was under the impression that the green wire coming from the head goes directly to the gauge - no splices or anything in line. Does this make sense? bad gauge maybe?

went from TPI to carb in this car and hacked out a bunch of harness stuff but I don't expect any of that to affect my temp gauge.

 

I had the same problem.
I gave up and glued a little rubber 'nub' or whatever at the max value, so the needle bounces off of it and doesn't get stuck up there anymore.

It's practically invisible.

 

I had that problem too. I glued a small piece of one those straws that come on the side of a WD-40 can to the top. It worked like a charm and it looks like it came from the factory that way.

 

yea I had been thinking about a screw or something. Those are both good ideas.

After playing around with gauges for a couple days now, it seems that most gauges have a slow needle, meaning there is some kinda mechanism to stop the needle from moving too quickly. My guess is that this mechanism is busted in my temp gauge. For now I guess I'll try the glued straw or something, but I'm guessing a new gauge would fix the problem.