I could use a 1974 slant six manifold heat control valve expert!

Thanks, Dan. And thanks for the recommendation about the correct manifold heat control valve solvent. I went out and bought a can of the Mopar Rust Penetrant that you recommended and lubed the shaft up with it. Everything works perfectly and smoothly right now - just like a brand new valve. That stuff is amazing!
I wasn't aware the stuff was still made. Can you post a pic and a part number?