Too much cam?

If you are supposed to be running the vacuum advance off manifold vacuum, you have it connected to the wrong port. Cap the one where you have it (in the side of the metering block) and plug it into the port under the front bowl in the base plate. Then try it. I'll be honest, i'm not a fan of FBO, so I would suggest get it the way he tells you to run it, and then see if it works for you. You have it connected wrong now.