Still has a stumble/hesitiation

sounds like your carb is mechanical secondary? I have a 750 mighty demon w/annular boosters, mechanical secondary on my 318...bought new, it came stock with 70/77 jets. when I had a .223/.230 cam I ran it with 68/75.......now with .244 @ .050 running 72/79 jets
no bog issues.....strange that the motor would ping at 34 total unless its lean..34 is usually the recommended timing, although on mine I can go to 38 without ping @ 1300 feet. what is you fuel delivery system? filter? line size? sorry I cant help more..good luck.