Copyright (c) 2002 By
David Thorne Smith
All rights Reserved
* DISCLAIMER *
I haven't tried this so can't guarantee it will absolutely work. I will say that I am 99.9% sure it will though.
I was looking at the factory DuraSparkII distributor and the stock distributor on the old 289 the other day and got to thinking. (Might NOT be a good idea for me to think), but this might benefit some of you with stock distributors especially if you are running Pertronics instead of points. Should work with a point system to. The distributor on the 289 is a 68 model, but I think they were the same for all 260 - 302??? No guarantees here either.
Not sure what year ford switched from points to MSD, but this should work with distributors from that time to the time they finally went to a DuraSparkII distributor from adapting the old style distributor. (I think in the late 80s, but could be that 86 was when they changed to the screw on adapters.) In any case if you run across a 1985 mustang GT (Manual Trans) and ever plan to go to a roller cam and MSD then grab that distributor because unless it had been changed out it should have the steel gear for a roller cam already. Anything else would likely have the cast gear.
For the year I know they used this setup would be 85. (probably anything below that with DuraSparkII and anything above that before they redesigned the distributors for DuraSparkII rather than points.) This is for the 5.0 liter engine only. It consists of an adapter that clips on top of the distributor just like the old styled cap. Then there is a rotor for it and the wide distributor cap that fits that making it look and act like a DuraSparkII distributor. I've taken measurements of the shaft diameter and height. They both appear to be the same so this setup should work fine for either points or pertronics.
The adapters are a little high priced if bought at an auto parts store, but I'd expect you would want to visit a wrecking yard and try their prices. You should be able to buy all of the parts at a good auto parts house though. All you would need is the adapter that clips to the top of the distributor. (Not one that screws to the top of the distributor), the rotor and cap if you don't want to buy new ones. They would be found on probably any of the 302 / 5.0 liter motors that used this setup. Not sure about the I6 guys, you would have to experiment. Remember what model car you got it from so when you have to buy a new cap and rotor. The adapter should be good from then on.
On the old 289 I'd already gone to a 4 brl manifold and carb from an 85 mustang GT (from a 2 brl factory setup). I then later went with the pertronics system and used their flame thrower coil to boot. I didn't bypass the resister wire like some say you have to do. I also gapped the plugs at .050 and never had any trouble. If I ever rebuild that engine I will go with the DuraSparkII adapter cap, rotor and cap as mentioned above and keep the pertronics. I believe the reason Ford did that to start with was to widen the area between the spark plug terminals to make sure there was no cross firing between them. On a pertronics system with wide spark plug gapes and hot coils that should perform the same function. Unfortunately on my 289 this turned out to be a bad thing because the engine wrapped up a lot faster and higher than it ever had and eventually started knocking. I'd suggest this setup or even MSD only on a fairly recently rebuilt engine and not one with high mileage on it like mine was!
Of course if you visit a wrecking yard and find a car with the whole DuraSparkII system and distributor system you may want to pay the extra bucks and get it all and use it. This suggestion is just for those who don't want to do that, but would like the look and possible benefits of the wider DuraSparkII cap and so on. You may need some longer plug wires if you are going to the larger cap from the old style, but in this case you would have to have them if you switched to MSD anyway. If they are older wires then you would probably want new wires anyway. Then again there is the chance that the wires would be long enough as is because there wouldn't be a real big difference needed in length. You wouldn't want to get plug wires for a newer engine because they would have a diifferent firing order and the plug wires wouldn't match up for the older firing order with the newer cap.
Again what you would need.
Adapter that clips on to the top of the distributor. (uses the same clips on the distributor that holds the stock distributor cap on)
(1) You would remove your plug wires marking them for where they should go.
(2) Remove the old cap and rotor.
(3) replace the old cap by clipping on the adapter.
(4) add the new rotor
(5) clip on the new cap.
(6) add the plug wires back to the correct terminals.
Should be a fairly fast and painless conversion and you probably wouldn't even have to mess with the timing to keep it like you had it, but would be a good idea to check it anyway.
Anyway hope this benefits some of you.
The red arrow shows the clip that holds the original distributor cap
on while the blue one shows the clip on the adapter that holds the MSD
cap on. The rotor inside the adapter is taller to make up the difference
between the height of the adapter and the DuraSparkII cap.
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