just realized i started in the wrong place

[Col. Mustard]

Hey everyone I'm Levi just joined the forum, haven't had a chance to look around but seems like a great place. I have a 73 c10 with a 250 and 3 on the tree, has been a pretty good workhorse until recently.

Couple weeks ago I found out the head was cracked, got a new one slammed in and got the truck running great. Only issue is the temp gauge The one on the water outlet/thermostat housing broke so went to use the one on the head. Using the stock wiring it would either bounce all over the place or redline within 5-10 minutes. Put a equus mechanical gauge in and sat at 195 for 20+ minutes idling, but as soon as I start driving it will fluctuate between 195-230ish. Took it to a shop and they are telling me that the sensor in the head is for a light (which I don't have) and the one in the tstat housing is for the gauge, at this point I don't care which is which im just tired of not driving my truck.

Anyhow thanks in advance for any help and hopefully I can return the favor sometime