I'm relatively new to this site and in the process of doing a mild restoration of an 84 TA (original LG4 motor with 130k miles). In short, here's the problem: I installed new spark plugs yesterday (AC Delco Rapid Fire) and, even though the engine runs fine after the change, the engine temp gauge is just slight above 100 (the bottom number on the gauge). It usually reads steady at 150 after the engine has warmed up. There is electrical power to the gauge, so I'm wondering what I could have inadvertendly damaged in the process and how to fix it?

Thanks in advance,