[s55mercury66]

I got busy with another project today, and didnt get to tinker with it today. The distributor is in good shape, it has 34,ooo miles on it and no wear I could find anywhere. Everything cleaned and lubed on reassembly. I will be playing with the vacuum advance to see if I can get it to center the points plate a little better, if it will retain the advance characteristics I need. The spare distributor I have looks like a replacement, that was installed on my donor motor when it was poorly rebuilt. Sounds like some of you are as surprised as I was to find out there was that much dwell variation, I appreciate all the replies.