Uh Oh !! Bad knocking !!

I'm hoping for Pishta's story, that's for sure. That could explain the 5-deg rise in temperature. I didn't look into the coolant yet (it's still in the parking garage at work--I took an Uber home). Or, something like SGBARRACUDA's suggestion would be nice. I was thinking it might be a rocker arm issue because the sound seems to be coming from the top not the bottom, but that's a big guess.

Well, fellers, I hate to do it to ya, but it's probably going to be a few days before I can give you more information and/or take a closer look. Me and my wife are moving tomorrow (I know--buzzard luck), and I'll be putzing around in the modern sedan for the next week or two. This time of year, the Dart is my daily driver. I hate to see her laid up like this !!