Duraspark II

[emunder]

I know...this has been covered numerous times and I have done my research & digging through all the threads...that's how I got this far lol. Ok as I'm getting further and further into working on this truck I think I want to do the Duraspark II setup. Spent the past few nights researching as much as I can on this subject here, on other forums & online. Narrowed my parts list down to the following below, do y'all see anything that I may be missing? Kind of foggy on what type of carb to get. Saw here where someone got one for an older F-350...Carter YF?

1. Harness - I'm going to take a look at the junk yards & see if I can find the stock harness. If not I think I'm going to go with the American Autowire harness p/n 500918. Seems to be a much better option than the Painless.

2. Duraspark Unit - These are readily available and I def want a brand new unit. Motorcraft p/n 1U2Z-12A199-AA.

3. Distributor - Another forum member on here posted that they used the Spectra Premium p/n FD11. This looks like a fine option or should I be considering something else?

4. Coil - Easy to find...lots of options here.

5. Non-Feedback Carb - Again...the non-EGR Carter YF from an older 1970 F-350? Not sure how to search for the right carb because a bunch of options are pulling up. Suggestions on this?

I've even looked into the possibility of doing the Offenhauser C manifold matched up with the Holley 390...that would be real cool! But then I'd have to swap the exhaust manifolds out for the EFI duals at the very least. I do plan on getting the exhaust replaced and removing the CAT all together. With the age of this truck in Texas they do not do emissions testing, just a safety inspection.

Considerations - Going to have to figure out which wiring to remove. Hoping I can pull the computer all together, just need to make sure the harness I get still allows the oil & temp guages to work. I plan on removing all of the smog crap. One thing I am worried about is how to block the EGR hole where the carb mounts. Saw where someone here found a conversion spacer without the EGR hole but that looks like it's totally impossible to find. Is there maybe a non-EGR manifold that I could pick up that would work?

Think that's pretty much about it. Still researching the subject for the best parts & how to do it properly. Hopefully I can pull it off lol.

[85lebaront2]

Up through 1977 the F150 and heavier 300 had a non-feedback Carter YFA for a non catalyst application, any non-computer Carter YF or one of the Holley 1940 replacements will work well, just be sure the "stack-up" height is the same as the feedback one, or the air filter may not fit and work.

[emunder]

Up through 1977 the F150 and heavier 300 had a non-feedback Carter YFA for a non catalyst application, any non-computer Carter YF or one of the Holley 1940 replacements will work well, just be sure the "stack-up" height is the same as the feedback one, or the air filter may not fit and work.

What is the difference between the YF & YFA models?

[grumpin]

What is the difference between the YF & YFA models?

On the EGR, do some research, it’s not a bad thing to have. If your engine will run good with it.

I can’t get my 460 running good with it so I have a plate on there to block it off. Going to have to try again some day.

[emunder]

On the EGR, do some research, it’s not a bad thing to have. If your engine will run good with it.

I can’t get my 460 running good with it so I have a plate on there to block it off. Going to have to try again some day.

Have to have the non-EGR, non-feedback carb though for the Duraspark setup to work correctly though right?

[Gary Lewis]

Have to have the non-EGR, non-feedback carb though for the Duraspark setup to work correctly though right?

Not sure I understand what you mean about having to have no EGR, but a carb from a non-EGR truck will work just fine.

However, if you use a distributor from an engine with EGR you will need to have it recurved. That's because the inert exhaust gas that is introduced into the air/fuel mix slows combustion significantly, so they give a lot of ignition advance via the vacuum advance unit. So if you do away with EGR and use a dizzy w/o recurving it you are likely to have at least pinging if not detonation.

As for your question earlier, I think the YF is a non-feedback carb and the YFA is a feedback carb. But I can't prove that.

Concerning the spacer to block off the EGR, David found one in this thread. Don't know if it still there.

David/1986F150Six has a Carter YF 4901 S carburetor [from 1970 F350 with 300 engine] on his engine and it works out really well.

[grumpin]

Not sure I understand what you mean about having to have no EGR, but a carb from a non-EGR truck will work just fine.

However, if you use a distributor from an engine with EGR you will need to have it recurved. That's because the inert exhaust gas that is introduced into the air/fuel mix slows combustion significantly, so they give a lot of ignition advance via the vacuum advance unit. So if you do away with EGR and use a dizzy w/o recurving it you are likely to have at least pinging if not detonation.

As for your question earlier, I think the YF is a non-feedback carb and the YFA is a feedback carb. But I can't prove that.

Concerning the spacer to block off the EGR, David found one in this thread. Don't know if it still there.

David/1986F150Six has a Carter YF 4901 S carburetor [from 1970 F350 with 300 engine] on his engine and it works out really well.

I forgot to mention, I found an EGR block plate on ebay I think. It was listed for a 351W, but had the dimensions so I ordered it and it worked.

Different engine and carb and all, but thought I’d say something.

[Rembrant]

2. Duraspark Unit - These are readily available and I def want a brand new unit. Motorcraft p/n 1U2Z-12A199-AA.

Readily available is right. The mail man dropped one off to me today;).

 

[emunder]

2. Duraspark Unit - These are readily available and I def want a brand new unit. Motorcraft p/n 1U2Z-12A199-AA.

Readily available is right. The mail man dropped one off to me today;).

Nice!

[LARIAT 85]

Have to have the non-EGR, non-feedback carb though for the Duraspark setup to work correctly though right?

A DuraSpark II ignition system would have originally used a non-feedback carburetor and a DSII-specific distributor that are both calibrated to be used with EGR and other emissions equipment.

You can use the DuraSaprk II ignition without EGR, but choose a carburetor that is not calibrated for EGR. Aftermarket carburetors like the Holley 390 are not calibrated for EGR. The easiest way to to do this is to find an older, stock FORD carburetor that was used before EGR (and other emissions) and one that closely matches your engine, transmission, and type of vehicle. The 1970 F350 carburetor you are referring to is a good example.

You will also need to re-curve your distributor so it is calibrated to run without EGR for the reasons Gary mentioned. There are a couple of places that sell DSII distributors that are calibrated to your specific engine combination.

Capiche?