I wish I had some good news here. I know that many members have chimed in trying to help.
The 750 made the engine idle much smoother. I was actually able to get it to idle down to 600 in gear without stalling. I wasn't able to do that with the 850 because below 700, it loped around and felt ready to stall.
The A/F numbers looked decent. Idle was in the 14.0 to 14.5 range and while sitting at a stoplight, it was in the 13.8 to 14.2 range. I was amazed at how docile the engine seemed. Part throttle A/F was just below 12.5 and no higher than 13.4, so that seemed within range.
It still detonated at 3/4 throttle and above. I even reset the timing to 17 initial and 31 total before the drive.
Everything that I have tried since the cam swap has resulted in detonation. Bigger jets, smaller jets. Bigger PVs, smaller ones. Different timing settings. Different distributors. A different carburetor. Different weather outside. Cool engine, warm engine. The only time it ran without spark knock was when I had the timing set to 6 initial and 20 total. That was only a test to assess things. I would never expect this engine to run right at that setting.
Currently, I am out of ideas.