[KobraKarl]

Todd,

exept for the timing light twitch, the rest of your symtoms sound like a very lean carbureator. popping and running crappy til your main fuel circuit kicks in... have you try backing out your idle screws? Admittedly I know nothing about msd or electronic ignitions but .......a little timing light bounce is not unusual with vacuum or centrifical advance distributers as they twitch a bit with every fuel variation..good luck ! KK