Nate - I am not sure how to interpret your last post. However I did go out and take a pic of my switchover valve ('81 300SD) and looked in the manual - because I forgot where the ALDA is.

Here is what I found - the vac line on the bottom of the switchover valve definitely goes to the ALDA. The vac line on the top definitely goes over to the back of the valve cover; however the nipple is not on the valve cover as I had remembered - it is actually just to the passenger side of the back of the valve cover. I am not sure exactly what that nipple is attached to. If my FSM were not so difficult to use, I would try to find it.

So in picture number one below you can see a red arrow pointing to the vac line going to the ALDA from the bottom of the switchover valve. The white arrow points to the vac line which travels over past the valve cover and attaches to a nipple there.

In picture number two you can see where the top vac line attaches. Assume it is the same in the PO's vehicle.