manifold vaccum for vaccum advance ?'s

Another reason i think the rings are fine is cause when i first fire up the engine it never smokes out the exhaust, and while its at an idle it never smokes, it never smokes upon acceleration, the only time it will smoke is when you get on it pretty good and let off the throttle. And it only does that while driving. If you in park and rev it up and let go of the throttle it doesnt smoke then ether. It only happens when your driving it and do it.
In my past expirence with an engine that had bad rings it would smoke when you first fired it up and it would smoke while it was sitting at an idle and it would smoke when accelerating from a stop, it just plain smoked all the time. But this magnum only does it when backing off the throttle after getting on it pretty good nd thats it. So it makes sense the valve seal on the number 5 cylinder is cracked or hardned and is letting the oil by and thats why my number 5 plug is drinched in oil.