Changing thermostat. Any firm recommendations?

[biomedtechguy]

Yes.

Chuck the o ring and fill the groove with RTV silicone.

I've had that one I linked to in service for a few years now and no leaks, no problem. Still using the O ring since I installed it a couple of years before your RTV advice.
This one from Mancini:
BSP90820

 

[#41]

One guy running a 180 thermostat is not necessarily going to experience the same thing as another guy running the same. If you run an oil temp gauge you'll find that the actual engine temp is quite a bit hotter than the coolant temperature. How much depends on what type of driving you are doing, environmental conditions, gearing, etc.

 

[8formulas]

If you're having overheating problems at med to higher speed, it's likely a flow issue. the last Superstat I bought only had a 1" diameter opening. The EMP/Robetshaw ones are 1 7/16" diameter opening. They're worth it.

EMP/Stewart Components 301 EMP Stewart High Performance Thermostats | Summit Racing

Free Shipping - EMP Stewart High Performance Thermostats with qualifying orders of $109. Shop Thermostats, Mechanical at Summit Racing.

www.summitracing.com

Yes, agreed!!!! This is the one I use in my car. Spend the money, it's worth it.

 

[tak419]

I'm no cooling expert. I started with a 180* with my sixpack, it ran good. I had a radiator problem and at that time I changed to a 195*, per the sixpack tuning guides suggestion. My car runs good, plugs are an excellent color, idles, starts even when hot. But it seem hot under the hood. Is the more power (?), I can't tell. Is it actually hotter under the hood than the 180 (?), that was hot also. I think conditions will make it all very of how hot it feels and runs, fuel from different stores at different times will make your power very. Everyone's cars are different due to their location and situation. Try the 195, seems to hot, put back in the 180. Thermostat change isn't a big deal. For me, they both work good.

 

[hunt2elk]

Not a thermostat recommendation, I do run the Robertshaw high flow design however. But as far as a gasket is concerned, these are the cats ***. Quick, easy, and reusable. I gave up on the paper gaskets years ago because they always leaked. I threw them in the trash and just used silicone. Works great, but takes time to clean when replacing a stat and you should let the silicone set overnight before adding fluid.
Thermostat Housing Gasket - MOPAR V-8 ENGINES - Part # RG-53063 SILICONE | eBay

 

[biomedtechguy]

I have so little time to work on my Roadrunner. I'll add a relative update.
I'm still THRILLED with the O-ring thermostat housing I posted about and I mentioned that I had removed the T-stat to "experiment" and just reinstalled the housing, no leaks!
Billet Specialties Aluminum Water Neck
My experience running no T-stat? Too cold in the winter around 140° but running around 180° in the brutal heat + humidity we have had for the last month.
I still need to install the factory/Mopar fan shroud around my flex fan, and the 2 SPAL 11" pusher fans are working great, each on their own independent relay and power circuit.