I have annoyed the car gods. Sigh!

Yhe only thing that can jump ecactly 180 degrees is the drive tip of the distributer in the oil pump driver slot. Centrifugal force seperated the 2 parts which means the distributer hold down was waaaaay to loose. Think about it... when it sat back down after the backfire it could only land right or wrong. Scares me though, loose parts and 5000 rpms can kill.