318 Engine stumble

So Speedmaster, not Skip White? Well that looks more like what you show. Still Chinese made....

Moving the distributor a tooth will not change anything. You will just end up rotating the body of the distributor to match how much the shaft rotated and end up in the same situation.

You really don't need to understand why the reverse polarity throws this firing location off, just that it DOES. Look at this link again:
MSD HEI new module timing off big time? - Speed Talk

Go down and look at the picture with the 3 pickup coils shown side by side. Take yours out, and compare to to the pix to see which you have and then go, and buy the one with the opposite wire colors.

And yes I think you have 2 or more problems going on.