I have the exact same setup as yours minus the MSD. The only thing different is I have the flat tops and cam. One thing that I have found, and I'm glad you did too is that a 650 is not enough. I've got one on my 400 now, and it isn't enough. I have a Comp Cams 270H Magnum. It idles good. This will give me a little more HP, and less torque I'm thinking.

Good Job. It's nice to see someone who has dynoed a 400.

Later
Riley