Upgraded my alternator and now my temp gauge is reading way hot

[Newguy71]

I recently installed a new alternator. The new one is like a 63 amp, my previous one might have been around 40amp but I'm not sure that matters since it was still hooked up through the original voltage regulator. I disconnected the voltage regulator and shorted the wires together like it says to do in the many threads about doing such an upgrade. I then picked up one of those nice red batteries that cost a fortune. Since then, the truck runs fine and my battery gauge seems to be working good. It'll change based on my rpms so I assume it's working good. What has seemed to stop working correctly or at least the same as before is my temperature gauge. I'm running the 190°f thermostat. Before the upgrades, my temperature gauge would run up to hot and then drop a little above the middle once the thermostat opened up. After the upgrades, it runs past hot, then dropped a tad maybe but never gets back down past hot until I slow down to a stop. And even then it still sits higher than expected, roughly 3/4 of the scale. I pulled over several times on a 15 mile trip to check and make sure it wasn't really running hot. I am thinking it has to do with my alternator putting out a higher voltage and therefore changing how my temperature gauge reads?? Anyone else had this experience? Any input?