Thermostat gasket leaking AGAIN!!!!

So I'm late to this party, but here goes. At some point Chrysler switch from cast iron to aluminum thermostat housings. The aluminum ones are terrible for warping and no manner of sanding will fix that. I have found that if you get a replacement housing from NAPA (Dorman 902-3012) it has been that it comes in cast iron with a machined face. Take a magnet when you go to pick up the part. here's a link, look at the picture of the sealing face - https://www.napaonline.com/en/search?text=thermostat housing&referer=v2. I have had great luck with the cast iron units, both with regular gaskets using Ultra Grey permatex and thread sealant, and lately with the silicone Real Gasket ones.