Tube fitting on side of Distributor

[cuz]

It's really up to you. I assumed you would use the vacuum side of the pump as designed. If you did, you would connect the pump to the intake since the purpose of the vacuum pump is to boost the available engine vacuum.
Any open port will act just like a manifold vacuum leak. The distributor would be an open port (meaning no resistance to flow). This would become an excessive vacuum leak and normally causes a very lean idle mixture which normally results in a high idle. This is exactly the same thing that happens with any intake manifold vacuum leak.

Since you are geared to the jury rigging mode (nothing wrong with that) I must ask why you even invested in a dual fuel/vacuum pump when a cheaper civvy fuel only pump would work just fine? Then run a single tube from the distributor to the manifold port that the vac pump was connected to and insert a 0.040 restrictor there and put a small axle type filtered vent on the distributor. Then set your idle mixture as needed.

[ZGjethro]

Thanks Cuz. My understanding of vacuum pressures is limited, but I understand how a vacuum leak would result in a lean condition. I will try the restriction and get back here to let everyone know how it works.

When I got my truck from a wildfire fighting district, a lot of the vacuum and vent lines were off and I did not want to replace ones which were not needed or desirable. The fuel pump has been bypassed and there is an electric unit in the back of the truck. I like your idea of running a line straight to the Manifold and putting a filtered vent on it. I am looking for simplicity and a clean install.

I do not know why the fuel pump was bypassed (bad diaphram?). The vacuum side of it is not operating the wipers and I am not sure if the pump or wipers are to blame. I might make a block off plate and remove the whole fuel pump.

This is my first old vehicle, and I have really enjoyed tinkering with it.

[cuz]

Go to electric wipers and you can just install a cover plate over the pump mounting hole. If you want to keep vacume wipers you will need the vacuum pump installed and the line from it to the intake manifold would be for the vac pump and the line from the vac pump to the wiper inlet will then need a "T" in it and then a restrictor in the "T" port that goes to the distributor.