Delving into a world I know nothing about. But is the advantage or purpose of the dual vacuum port distributor over the single. My truck has the dual vacuum model. But for the sake of simplicity was wondering about a single port.

 

I've never actually seen or had a dual vac. But from what I understand, the two ports work opposite of each other. One of them is the vacuum advance, and the other is the vacuum retard.
I can definitely see the benefit to one. When you have a lot of base timing, it can be really nice for performance, but can cause kickback and even wear on the starter every time you fire it up. So, having that timing retard feature on the dual vac distributor can overcome that by bringing it back down when you fire it up. I also think you have more low end torque with a lower timing, so it can come into play with that too.

The downside that I can see is that's a really intricate vacuum system with vacuum only going to one port when you need more timing and vacuum only going to the other port when you need less timing.
If you don't need the retarded timing feature, you can eliminate a lot of complexity by only having the single port.

But, if it all works, it seems like a great system.

 

I ran across some reference to manual gear vehicles having the dual port while auto's having the single port.
I am moving to a c4 on this truck, so that piqued my interest.
Just wondering if for the sake of simplicity I ought to dump my existing dual port and install a single port.

 

I don't think you'd really run into any issues with going to a single port. From what I've seen, the dual port is a bit of an older setup (neither of my '80s 300s with a manual transmission had a dual port).

Dual vacuum advance distributor - Ford Muscle Forums : Ford Muscle Cars Tech Forum

 

Had not ran across that one. Then I wonder if the pertronix on my dual port would work on the distributor with the single port?
"one thing leads to another."
Great song for working on these trucks.

 

I am going to go ahead and order a single vac distributor. I would like to remove the oil pump drive shaft from the old one prior to turning it in for a core. How does one do that. I can't figure it out yet. Have not tried much force.
I have a new shaft for the new oil pump and I don't have a clue how it installs, unless it just pushes in and clips on the grooved portion at the top of the shaft.

 

Just give it a tug. If it's stuck, get some pliers and pull harder.
There's nothing like a screw/bolt holding it in there. Just a "tight" fit.

 

I was leary of the swift, strong tug approach as I thought I read about a clip inside that held it. So I am good with that now.
Made life easier with a power steering puller kit (borrowed) and ordered a replacement pump.
Have belts for both P/S and alternator;
Lost my fan mounting bolts, so had to cut down and thread some more for the fan/spacer.
And cleaned up and painted my air breather (also, for grins used some enamel black paint and an artists brush and painted the Powered by Ford on the valve cover - a little shakey but looks OK at 5 feet and painted an accent stripe around the base of the air breather cover - trying to put lip stick on a pig, I suppose).
A distributor (single vac) is on the way along with some new spark plugs (motorcraft).
I tried out the approach of lining up the engine on top dead center;
1. cranked engine around to front cylinder being at its peak which is also correlates with the crank shaft groove (not correct) lining up with 0 on the timing mark indicator on the top left side of the timing gear cover;
2. turned it over to make sure it was blowing air out the spark plug hole.
I am thinking that when I install the new distributor, I will point the cutout in the shaft (where the rotor sits) towards number one cylinder.