Just installed new MSD computer controlled distributor, and set idle at 10° and locked it down. It's popping in the exhaust. When I set it to 20° it runs fine. I've checked TDC and the balancer and everything is right. Then I synchronize it all at 30°. The propagation is set at 800 for it to read 30 when revved. I don't understand why it seems retarded at 10°.