Vacuum advance on distributor

[Smedley]

I did quite a few searches on the subject and found several answer but none of the setups were the same as mine.

Where do I connect the two vacuum ports on my distributor. 302, stock distributor w/Crane Cams electronic ignition module, and a FiTech Go Street 400. I have one small port on the back of the FiTech that is capped and still available.

It runs pretty smooth now. Idle around 780 rpm, 8* timing. I have only driven it around the neighborhood a couple of times, most of the running is in the driveway.

Thanks,
Will

 

[DirtDonk]

Unless you still have every other item that was originally on the engine that was used to control timing, you don't use the rear port anymore.
That is a retard port, and the front port is advance. Originally there would have been several additional vacuum tubes running between the carb, the intake, and a little diaphragm thingy bolted to the back of the intake that all worked together to decide when it was a good thing to advance the timing, and when it was a good thing to retard the timing.
Right now you only need advance.

Leave the rear port open and run a hose from the front port to a "timed" vacuum signal port on the throttle body.
You can also try full manifold vacuum as some have good luck using full vacuum to the distributor. Most of us end up with timed, or ported vacuum.

What does it say that port is for in the FiTech instructions? Does it list a timed/ported fitting?

Paul

 

[71broncman]

While you're at it, this would be a good time to check the vacuum advance can to see if it's still functional. Pop the distributor cap off and apply vacuum (vacuum pump or by mouth) to the hose. If the arm from the can pulls the plate, it's good. If it just sucks air through replace the vacuum advance can. Quick and easy check.
Mark.

 

[Broncobowsher]

The port closest to the cap, leave open so it can breath. Connect nothing to it.
The port furthest from the cap, connect to the "ported" vacuum fitting on the throttle body. Check the instructions for the EFI to get the right one. It is different than full manifold vacuum that most of the ports are.

 

[Smedley]

Paul. The port on the back is the for ported vacuum. (Distributor Advance) I'll get some hose to today and hook that up. Should I leave the rear port open or cap it?

Mark, I'll check the vacuum advance tonight.

Thanks,
Will

 

[Justafordguy]

Should I leave the rear port open or cap it?

Leave it open.

 

[Smedley]

Vacuum properly hooked up now. Running smoother each day.

Thanks for the help.