Welp.. I THINK I got it. Exhaust leak. Can't be 100% sure yet. Ordered a ceramic coated patriot 4->1 from IPD. Reassembled head. New gaskets, etc. Fired up today. The patriot is still leaking from one of the 4 ports, can't nail it down just yet. BUT.. the stethoscope is showing no tapping from the head. Maybe I am just lucky and soon it will resume the tapping. But for the moment, it's looking good. The car is much zippier throttle response with the Patriot. That old cast iron thing was cracked almost in half.
One thing about the Patriot. The dual SU manifold did not fit up perfectly. Had to notch out the exhaust flange a bit. Not too bad. And the Patriot is making ever-so-slight contact with the oil filter. Not thrilled about it, but maybe I can clear it with a different filter make.
More later after first test drive.