WHY?

I have run the Fel Pro 1215 intake valley pan ever since my first 440 in 2002. California weather, no snow. Tennessee ? Unless you are in the upper East corner, your weather is similar.
I always use paper gaskets on both sides of the valley tin. I currently have thick head gaskets on the engine so I use a Mr Gasket super thick intake gasket to make everything align right.

Tennessee gets some snow, slick. I hate to tell you. I have friends in the west, middle and east in Tennessee and they all see some snow and cold every winter. Trust me. It ain't just the upper east corner. I bet Leanna @CudaChick1968 wishes it was. lol