Need help tuning Quickfuel carb

Ok guys, it’s not the carburetor.
I have successfully determined that today.
It’s in the distributor somewhere.
I fired it up this afternoon let it warm up comkmetely and put my timing light on each cylinder and brought the rpm’s up to 2500 rpm.
All 8 cylinders are showing a missfire in the timing lights strobe, there is an obvious huge break in the strobe light when it’s missing.
I reach over and un-plug the vacuum advance and plug it up and bring the rpm’s up to 2500 and it’s smooth as glass on all 8 cylinders and no missfires.
So the vacuum advance is causing whatever is going on, it has to be ether rotor phasing, or when the vacuum advance is applied the reluctor to pick up coil post gap is ether too tight or too far away.
That’s the only things I can come up with at this point.
I’m installing my modified distributor cap now that has a 5/8 hole drilled into directly behind the number one cap terminal and I am going to take some
Pictures of the rotors position with and without the vacuum advance and I will post them up.