Acting like one cylinder firing lean.
Well, what I have now is a new MSD pro billet distributor with only mechanical. I bought some stoppers 10* & 14* so the highest initial would be 26*+10*=36*. From what I've read is that VA is not necessary. But I know what you guus are talking about, manifold vacuum gives more initial.
So tried messing with mixture again and the only way I could get rid of the random shake was to unplug my full manifold vacuum port. Drove it but when I came to a red light it would shake a little but go away. Same when slowing down to turn I can hear the header pipes smacking the body. I don't know anymore been troubleshooting it every weekend for 9 months now and I'm over it. Give it a couple more weekends, then to a classic auto shop.