|Converting your car to the Ford Dura Spark II ignition system is not only easy but well worth the effort. It not only gets rid of your points but gives you a very reliable and efficient ignition system. The Dura Spark II system is much more efficient than the best of the duel point systems, and in most cases will be all you need for stock to mild performance needs. If you are into very high performance you will probably want to go with an Excel, Mallory, or other high performance system that gives you more latitude in your application. I have a mild 289 in my Falcon and opting for a more expensive system would not give me any performance gains. You can buy and install the Dura Spark II system for a fraction of the cost of an after marker system.
The first step is to find a donor vehicle to get your parts from. The Dura Spark II system was built from 1974 through 1979, and possibly later in some parts of the country, also note that in California the Dura Spark I system was used a lot during the 1974 to 1979 time period. The Dura Spark II system is distinguished by the blue color coding on the ignition module. The distributor for the 260, 289, and 302 will all interchange. The 351 distributor will not fit. So be sure you are getting a 302 distributor. They were thousands of vehicles made with the 302 engines, so finding one is no problem.
My search for a donor car started with a check for engine codes before I left home. After checking a couple of 70s manuals I found that the engine code for a 302 was H. When I got the to the junk yard I started looking for a vehicle with the H engine code. However an H code does not guarantee a 302, when you are dealing with twenty five plus year old cars the engine could have been changed out over the years to something else, so buyer beware. It did not take long before I found a 1978 Ford truck with the H code. The engine was definitely a small block so I opted to remove the distributor and was hoping it was not a 351. While I was there, I also removed the connector plugs from the distributor, coil, and Ignition module, by saving as much of the harness as I could I then cut the wires where they entered the main wiring harness. The distributor and wiring cost me less than twenty dollars. While on the way home I stopped by the local parts store and bought a new D.S. II ignition module and distributor module, I already had a new coil. The only three things that can go bad besides bad wiring in the D.S. II systems are the coil, module, and dist. module. For this reason I wanted to start with all new components.
When I got home I replaced the distributor module with the new one and while the dist. was apart I cleaned it good and checked the vacuum diaphragm to make sure it was not bad. I also compared it with the 289 distributor from my Falcon to make sure it was indeed a 302 distributor. It was the correct one. I also compared it to a 351 distributor I had to see what the difference was and noticed that they looked almost identical. While looking at the bottom of the distributor I noticed that the oil pump drive shaft hex was larger in the 351 distributor.
I made the wiring harness first, by finding a suitable mounting place for the Ign. module and then measuring the distance I would have to go for the wiring harness to connect up properly. NOTE there two plugs on the Ign. module, plug one has a red and a white wire, and plug two has a green, black, orange, and purple wire. It is important to note that in many instances when the wires pass through the plugs into the donor vehicle wiring harness that the color code will change to another color, these color codes change from year to year and from model to model. When you make up your harness please be consistent and make sure the color codes on the wiring diagram I have provided are adhered to. For example, on the donor truck I got my wiring from the red wire changed to white as it passed through the plug to the donor vehicle wiring harness and the white wire changed to red. This don't make sense to me either so beware. In the final analysis be sure the red wire from the ignition module goes to run as in the wiring diagram regardless of the color of the wire on the plug you removed from the donor car. The white wire is spliced into the red-blue wire and so on, you will be OK. I made the wiring harness and wrapped it with black electrical tape and put it in the existing wiring clamps that were already in my car. To the casual observer it looks perfectly stock and nothing looks out of place. It makes for a very neat appearance. Should you ever sell your car to a purest, the whole thing can easily be removed without disturbing the original wiring harness.
If you want to make the system look unobtrusive you can retain your original black cap with the original wires. I opted for the larger cap and wires that most of the D.S. II systems used. I think there is less chance of having a miss fire. The system puts out a lot of spark and it could jump to another terminal causing a miss fire.
Once the harness and module was installed, I removed the distributor noting the positing of the rotor when I removed it. This is important because you will have to install the new distributor with the rotor pointing in the same direction to keep from getting your car out of time. Also note the position of the vacuum diaphragm. I had a snafu when I removed my distributor. As I pulled it out the oil pump drive shaft came out with it. I saw it coming and grabbed hold to make sure it did not fall back into the hole and possibly into the pan. It is beyond me why someone would not put the oil pump shaft retainer on when building the engine. With some careful maneuvering I was able to get it back in and engaged in the pump. I installed the brakerless distributor making sure the rotor and vacuum diaphragm was in the right position. With this static timing your car should start. Once you get it started you can use a timing light and set the timing precisely. With the distributor installed I put the cap on and installed the wires according to firing order. The number one socket on the cap is marked with the number 1. The firing order is counterclockwise 1-5-4-2-6-3-7-8. When you install your electronic system you will want to regap your spark plugs to 0.044 of an inch.
With your car timed look everything over and make sure everything is neat and where it should be, and you should be ready to go.
This is for reference only. People's mechanical ability varies and I can not be responsible for someone elses inability to affect the change over properly. You do so at your own risk.