If your timing was off, you’d wouldn’t be running fine after 5K, it should get incrementally worse as you rev…and if it’s off by enough it should throw codes/limp. Go back to the entire OEM setup and see what happens. As for the plugs regapping, no clue…they can withstand rediculous temps in the cylinder so I doubt detonation would heat distort them. You’d also recognize detonation via EGT as well. I’ll be free on Sunday evening if you need any help.