I have the feedback carb, etc. on my 85 F150, 4.9l. I'd like to get away from that and go to a duraspark ii. I can find all the parts EXCEPT the wiring harness!

I've called all over town and no one has anything that era in the salvage yards.

SO - What are my options? Are there other, affordable, conversion options to get rid of the feedback carb and computer? Is there another source for the harness and will ANY Duraspark II harness work?

I'm stuck....

(This is why I like my '63 - simple...)

 

The harness for the 6 is a bit different because of the location of the distributor & coil.

Aftermarket Painless harnesses are expensive, (~$130) but available.

You could always use an 'all in one' DUI type distributor to eliminate the computer.

 

I agree. Thats exactly what i did, except I went to the dark side and used a HEI one wire distributer with the coil on top. Easy to hook up and works great!

 

I'm looking at the DUI system but haven't used one before.
Do I understand this right? It doesn't use a separate coil?

The system is just the DUI distributor (with one hookup to 12v), Plug Wires and the new non-feedback carb?

Then timing is just set as usual?

That sounds way to simple...

Am I on track or ?

 

The HEI and DUI all in one distributors incorporate the ignition module and coil right into the distributor cap.

You can adjust the ignition curve with weights and springs.
Some models have vacuum advance too.

 

That is correct, all it needs is "1" 12V wire and thats it. It more than likely need a vacuum advance, unless you are making a racing truck. Very very simple, and very reliable.

You won't get all the benefits from a computer setup, but your fuel economy shouldn't suffer too much to even look back.

 

At the moment, I see more negatives than positive with the computer setup. Rough Idle, more to go wrong, etc..

Simple is better in my opinion.

Just need to figure out the best source for the 12v line to the DUI distributor..

 

Just use the hot wire that went to your TFI coil?

 

Yes, you are on track. The "Duraspark swap" is popular because not only is it a good and reliable ignition system, but stock FORD parts are used that can usually can be found in junkyards for cheap. And being stock Ford parts, you can find replacement components in any parts house in America. Except for the wire harness. As these trucks get older and cheap junkyard parts become less available, the "Duraspark swap" becomes more expensive and less attractive. If you cannot locate the Duraspark wire harness, there are plenty of complete aftermarket ignition systems you can use.

The DUI is the best one and the one I would personally go with if I had to go aftermarket. Like the GM HEI, the ignition coil and module are built right into the distributor. They work well and are simple to hook up...just one wire. And like the Duraspark ignition, if you need replacement components in the future, you can get them in any parts house in America; you just have to remember to ask for GM parts.

The downside is they are very expensive, very big, and extremely ugly. They are a GM design, and GM mounted their distributors in the back of the engine while Ford's are right up front, where the distributor will be front and center. They are HUGE, so your stock air cleaner might not fit.
And there is just something not right about opening the hood of a Ford and seeing a big ugly GM distributor right in the front.

 

I think I've pretty much decided on the DUI conversion. The last question is; what carb to use?

I was thinking of a YFA w/Electric choke. National Carburetor ND1506 seems t fit the bill



Thoughts? This should just bolt on and existing linkages connect?

SO...

DUI Distributor and Plug Wires
Carter YFA W/Electric Choke

Install new carb, install distributor, connect the 12v, connect the plug wires (in the correct order of course), set the timing and away we go...

(anything I'm missing?)

 

Are you keeping all the emissions intact?

YFA have the bowl vent nipple.
If you still have a functioning charcoal canister and the associated purge valves etc that would be the one.
If not, go for a YF model.