While I have my old engine out and finishing up my Hutton motor I decided to re-spray my engine bay. In preparation, I wanted to remove all components for respraying satin black. Then I got stuck trying to remove the heater core cover. Took all the nuts off the firewall bolts but it refused to move. After wrestling with it for hours over a few days time, I removed the blower motor so I could try and pry that lower left side loose. Still no luck. Finally I used my cell phone and snapped the following picture. As you can see, it was a sheet metal screw. Looking in passenger side of firewall, there it was, a 7/16 hex head. Removed that and cover came right off! I wonder if that was a factory quick fix or ???