My 400 is a pretty mild build for touring and has always done well at the factory 9B. I'm not understanding why yours is 13 degrees with the adv hose pulled at idle. Do you mean with a tooth off you could be atdc instead of btdc? It actually clears up at wot. It's mainly through the accelerating throttle positions when the vacuum is at it's highest. So doesn't that point to a problem with the advance? There is no changing springs on a vac adv dist is there, just mechanical distributors, correct?
