Be sure to use the "black oxide" hardened studs for the carb hold-down. The "silver" ones are soft and can twist easily, by observation.
In the middle '70s, I had a friend with a Ford 352 that he was "helping" a bit. He wrote to Edelbrock with some questions. The hand-written reply from Vic (himself?) regarding thermostat temp was that to use a 180 degree, as engine wear would increase with a 160 thermostat. This was in the era when OEM thermostats became 195 degree items from the prior 180 "standard".
Remember, too, that a thermostat is a flow restrictor, to ensure that the water does not move through the engine too quickly, so it can absorb what heat it needs to to keep things at the desired level. With the radiator then releasing that heat to the atmosphere. Many dirt track racers just use big washers with different-sized holes in them for their flow restrictors, in the place of a thermostat as such. Trial and error with the hole size.
Thermostats are inexpensive, as noted. The Robert Shaw item is the best design, but not the "common" design. The RS items were OEM with Chrysler for many years in the '60s and '70s.
For the '72 model year, Chrysler went with a 185 degree thermostat as OEM production on our '72 Newport Royal 400 2bbl. I asked the old-line Chrysler service manager at our local dealership about if that 5 degrees really made any difference. He kind of laughed and said "They'll run at the temp they want to". A few years later, Chrysler was at 195 degree thermostats like everybody else was, as a part of their emissions reduction package.
Back in the middle '50s, NailHead Buick V-8s used a 160 degree thermostat spec. But they also had higher-nickel content blocks and cyl heads, which made them harder and more wear resistant. But they still got too hot in the summer, in a time when a/c was not "everywhere". With THICK radiators that should have kept anything cool, but didn't seem to be able to, by observation.
ALSO, I might also mention that if the cyl block has not been "flushed out", that you know of, this could also be a factor in your situation. Knock all of the core/freeze plugs out of the block, flush out everything in the water jackets, front to back, then put new plugs in to replace the ones you removed, refill with water, pull the lower radiator hose and let the water drain out, then put the hose back on and fill the radiator with quality antifreeze coolant (about 2 gallons, as our a/c Chryslers usually take about 9 quarts).
You'll find that as the block is angled downward toward the cowl, the sediment from accumulated rust will settle in that rear area. Which decreases water flow back there, as a result. Which can also increase latent radiated heat from the block. It's a messy job, best done with the car on n overhead lift (rain suit suggested), but something that will put things back to what they started with when the car was newer. Not something many people think about when chasing "over-heat" issues.
Just some thoughts,
CBODY67
