Hi adobejoe, the stock DuraSpark II's (DS II) systems are so easy to swap in (I used to be able to do them in able an hour after gathering all the parts) and many of the parts are the exact same as were used on all the other Ford engines of those years with only a few exceptions. You would only need to find these specific items of 200 or 250 Six parts. A factory Ford 1976 to 1983 200 Six engine Ignition Wire Harness, a 200 or 250 Six DS II Distributor, a DS II Distributor Cap and Rotor for a Six, and a 200 Six Length Spark Plug Wire Set those are the only engine specific parts. You can use an aftermarket Ignition Wire Harness if you can't find the OEM. You also need a DS II Coil, and ICM (Ignition Control Modula). I often used to go and get everything from a junk yard to do the swap on the cheap. You can still get most everything new.
There are a number of ways to wire a DuraSpark II system (DSII) depending on how much rewiring of your Car, Truck, or Farm or Construction Equipment you want to do. Here is how I did it on a quite a number of early cars and trucks that is very simple and it keeps and uses all the car or trucks original wiring by only adding one or two new wires. Also if you should ever want to return to the old stock system it's easy to change back.
1. With the new or used DSII Distributor installed its 3 Wire socket plugs into the DSII Factory Ford or aftermarket Ignition Wire Harnesses 3 Wire Plug and then you can start to route the DSII wire harness. These are the Orange, Black, and Purple wires.
2. The Ignition Control Module (ICM) gets mounted to the inter fender well / panel and the DSII harnesses 4 Wire Plug gets plugged into the ICM's 4 Wire Socket. The Orange, Black, and Purple wires are connected to the distributor (as in above #1 by the 3 wire plug), the 4th Green wire goes to the Coils - or Negative Side and if your also using a Tach its also hooked to that same side. Some people run an extra ground wire to one of the mounting screws of the ICM if the inter fender panel is made of metal it probably isn't necessary but it also won't hurt if you wanted to, as you really can't have too many Grounds!
3. I used most all of the stock vehicle wiring including the Pink Resistor wire that goes to the Battery or the + Positive Side of the stock Ford coil. This Pink wire goes right into the DuraSpark II coils Red wire that's hooked up to the Battery or + side of the new DSII coil, this wire comes from the ICM's two wire plug (with a Red and White Wire). Note if you also have the stock Horse Shoe (See Below step) DSII Coil Plug its even easier and all Plugs together. Also if using the resistor wire or a ballast resistor to power the coil in the ignition switch's run position then the other Red wire coming from the I terminal (for extra voltage when starting) from the starter solenoid goes onto this same + Positive Red wire on Coil.
4. The DSII horseshoe clip is made so that the Green wire coming out of the DSII wire harness plugs onto the Tach or the - negative side of the coil, so you just plug it on as is.
5. The ICM's 2 wire plug socket is plugged into the 2 wire plug and it has a Red and a White wire coming out of it. I ran a new wire connecting this Red wire and splicing it into the Pink wire about 2 or 3 inches under the dash behind the ignition switch so that it's before the Resistor in the Pink wire, this give you a full 12+ Volts input going to the ICM. I even used a Crimp On type Splice / Trailer type Connector so I didn't have to cut any of the original wiring harness. If you have a Volt / Ohm meter probe the wire there you are looking for at least a full 12 + volts with the Key On in or in the Run position as the ICM needs to have a full 12 volts to run correctly. This is all you really need to make it run and many people don't even bother to hookup that White wire. However the White wire though is for the Ignition retard feature of the ICM and in my OPIN is a good idea to hookup easier on the starter. To do so just run a new wire connecting the White wire over to the I terminal of the starter solenoid and now your all done and can Enjoy all the benefits of the new DSII ignition system.
If you are thinking of making your own wire harness you could even customize the above instructions some by installing the ICM inside the car, in the truck cab or any convenient location on a piece of Equipment ideal is in a cooler location to protect the ICM and make it last even longer this would also make the system semi hidden if you wanted to keep a more stock looking appearance under the hood and then you could also use the DSI small cap, and rotor, and your current Spark Plug Wire Set for a very stock looking install on a more vintage looking model. If you wanted to up grade some of the stock grade parts, then an aftermarket Coil, Plug Wire Set, a Higher Quality Distributor Cap, and Rotor with Brass contacts is good very good to do.
A side note on the Ignition Control Modules (ICM's) many in the past that had early failure problems and these complaints were specifically tied to the ICM they were usually caused by using an inferior quality part so look for quality parts.
Sorry don't have any good pictures currently of the complete 4 or Inline Six DuraSpark II Ignition System Parts to show what they look like, but here is what some of the stock parts will look like for a V8 DSII system again all the parts are going to be exactly the same with the exception of you needing to use Engine Specific Distributor, with it's matching cap, rotor, and plug wires, etc. the below link also has a DSII wiring diagram.
The white wire connection is not absolutely necessary, but it’s function is to energize the “retard while starting” function of the Duraspark II module. When cranking the engine, the module actually retards the spark so the engine can crank easier. This allows you to run additional initial advance.
mustangsteve.com
http://www.wrljet.com/fordv8/duraspark.html
Here is an example of a New Replacement Motorcraft ICM for the stock DuraSpark II ignition system
https://www.amazon.com/Motorcraft-DY-893-Module-Assy-Amplifier/dp/B000EQ82UK