I just got a 72 wagon. Ran poorly and I found a vacuum line between the diaphragm on the distributor and the intake manifold was unhooked and the manifold capped. (I believe this is usually done temporarily when you time the engine.) Anyhow, after I hooked it back up the car ran like new. Really amazing difference. So my point is that the vacuum lines on both sides of the diaphragm on the distributor seem to be important (advances and retards the spark.) jt