Duraspark II hookup



We are going to install a Duraspark ll distributor in our 1965 Mustang. Where is the best place to find a switched 12V power source? Is there a good place in the engine compartment? I checked the "+" wire to the coil and the "I" terminal on the starter solenoid but both these only have a little more than 6V. Does this sound correct? If yes, is there a resistor somewhere (it wasn't obvious so I'm sure I just don't know where to look)? I plan to use the Ford control module and follow the Forum's instructions.

Also, David is always sure to point out that the vacuum control valve on the Autolite carburetor must be removed and plugged. Does anyone know what threads the plug should have?
Thanks for your help.
Sorry I can’t help concerning the 12-volt source. My voltage comes directly from my Jacobs computer.

I do have a question concerning your plans for the Vacuum Control Valve. This valve is nothing more than a calibrated diaphragm and spring. If this diaphragm is removed the vacuum source to the vacuum nipple on the autolite will not change. The vacuum source is still physically plumed internally to the ported and manifold vacuum sources.

Did David define how this port was plugged?

Anybody know any 12v sources? I'm going to be hooking up the DS2 this weekend also.

I guess there would be a couple of ways to go. Either off the back of the ign. switch (this gets you around the resistor wire that is giving you the 6V at the coil) or run a wire from the coil + to switch a relay that will provide 12V directly from the + side of the starter relay.

Either way it needs to be a switched 12V source.

Good luck, Ric.
The easiest point to find IGNition +12v on most Fords is right at the fuse block. One fuse will be labeled IGN. In between that fuse and the underhood "I" circuits is a length of resistance wire that causes the voltage drop you see (about 6-8v underhood).

Get one of those blue 3M wire taps and connect into the IGN wire where it comes out of the fuse block. Poke your new wire thru the firewall next to the steering column (you'll probably find several other holes that have extra room to use, as well). Be sure to use a 16 AWG or larger wire, as the DII system can pull 12 Amps on a cold morning.

Good luck!
Howdy All:

Tom and 66200i6- On plugging the "Spark Control Valve" on the Autolite 1100 carb, designed to work with the "Load-a-Matic" distributor- I happened to find a threaded plug in my possibles box. It's been some time since I used that original 1100, and I'm going on memory, so it's a bit scary, but IIRC, it was a fine threaded plug. Sorry, I can't be more helpful.

I found this change when I swapped my Load-a-matic distributor for a '68 with centrifugal advance. At first I plumbed the vacuum line to the carb and left the Spark Control Valve in place. I got very inconsistent and sluggish performance. Next, I plumbed to a manifold vacuum source, and got a solid signal and more vacuum advance- To the point that I had to retard the initial setting. This got me to worrying about the original "SCV" vacuum source at the carb. I had already plugged it, but got to thinking about; a possibly leaky SCV, and the function of basically, a vacuum switch pulling against a plugged line. It seemed to me that the SCV would still alter the vacuum function and internal signals of the carb. With the Load-a-matic gone, the SCV served no purpose. So, I removed and plugged the hole. No more worries. The engine definitely ran better, but I rebuilt the carb at the same time and tuned everything, so I can't say for sure that plugging the SCV was the key factor.

Sorry, I can't be more helpful on the size of the threaded plug.

Adios, David