I live in southern louisiana and it stays usually between 85 and 90 degrees here. I'm not really sure what temperature thermostat I should buy.
I would say nothing over 180 deg. I use a 180; we get summer temps 80 to 95+ in my area. I think 180, best all around stat for these cars. If the cooling system is not up to par, whatever stat you use, you will have issues.
Probably a 195. But they also corked the motors with 2 bbl carbs and tiny little cockeyed exhaust manifolds too. So obviously power was not the primary concern. 180 is a good all around temp if you need a little warm air in the eve's and defogger for the early am. Otherwise a 160 will result in a cooler denser intake charge and allows more aggressive tunes if you want that last little bit of power.
180 in socal with similar all around temperature, since I changed mine to this it never overheated and I just drove from LA to Phoenix and back! By 105° outside