Here I'm using India ink to see where these vac lines go. After doing my experiments with the vacuum and the '87, I traced the lines from the distributor advance to this spot on the carburetor. I know the 20R and 22R carburetors are different, but in this case they are the same. Luckily for me, the 20R distributor only has one port for vacuum advance, and there are three lines here and they all go to the same place. Two of them I'll be using to control the fuel pump diaphragm, and the other one