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?
That's my base idle setting. You actually lose vacuum during acceleration until the engine evens out (cruise), that's why you need the mechanical advance as well as vacuum. And yes, depending on which direction you are OFF on the installation, you could be advanced or retarded. You say it runs good at WOT, no pinging? Because in your initial post, you say you are experiencing a lot of pinging/detonation, that equals too advanced.
Last edited by Dr. Drivability; 03/16/1704:24 PM. Reason: added to post
