Coolant Temperature Gauge - Needle position when engine is warm

[texas-topper]

Hi All,
First time poster to the forum and I am looking for a little info. Last weekend I bought a fairly clean, 1978 Chevy Big 10 with 53K original miles. It has the 350-4bbl engine. It seems to be running cool (better then the alternative) and I suspect the thermostat is stuck open.

Could you all tell me where the temperature gauge needle should be pointing when the engine is warmed up? I suspect it should be somewhat to the right of the long, center vertical tick mark on the gauge. Also, let me know what temperature thermostat your running. I believe GM installed 195ºF thermostats, but I am leaning towards putting in an 180ºF to deal with the central Texas heat.

Thanks for the help!

Ken