I have an '84 F150 with the 351w with the original motorcraft 2 barrel carb. The previous owner didn't drive it a lot and the carb has some issues and the emissions system is all unhooked and doesn't work. I have a limited buget right now so I am trying to figure out the best route to take with it to make it a little more dependable. I have an autolite carb off a late 60's model ford that I plan to rebuild and install on the truck. My question is can I install the Autolite carb on the engine with the original TFI ignition system or do I need to convert it over to a duraspark ignition system?

 

To have it work right you need to replace the TFI dist.
Dave - - - -

 

A more lengthy answer is "Yes, you can replace the feedback carb with a non-feedback unit. However, the truck will drive poorly, have little power, and get miserable MPG."

The computer knows whether the feedback carb is there or not, and if it isn't the computer locks the ignition advance into limp-home mode with no advance. The 1982 I bought several years ago had been sitting on a car lot for years exactly because of that. A DS-II conversion fixed it.

 

Thanks for the info. Do you know where I could get a DS-II conversion kit at?

 

As far as I know, there is actually no "conversion kit". You'll need a DS-II distributor, a DS-II module, and the wiring harness. The distributor can be one from the parts store, and mine was happy to take the non-DS distributor as the core. The module is any blue-grommeted module, available from eBay or from the parts store. But the harness is really just available from a salvage off a DS-II truck - and preferably one with the same engine as yours. However, the 302 took the same harness as the 351W, so you can use one from that engine. And, with some wire lengthening you can make one from a 300 six, 351M/400, or a 460 work.

 

Thanks so much for the info! I really appreciate it!

 

If you go to the salvage look for a truck with a vacuum advance line to the distributor. That's a DS-II distributor. If it is a 351W get the distributor, harness, and module - which sits on the driver's fender liner. And the harness is just the bit that connects to the distributor and the module plus the truck. Not the whole engine compartment harness.

 

Not inexpensive, but another way to handle the wiring: https://www.summitracing.com/parts/PRF-30812/

 

Thanks for the info guys I really appreciate it. My last question is if I get all the stuff I need to do the swap is it all plug and play with the chassis harness? Do I need to remove the original computer?

 

No, you don't need to remove it as it only controls things you've removed or replaced, like the carb and ignition. However, you can remove it as it isn't doing anything. I believe the '84 had the computer under the dash. And, its wiring harness and sending units are separate, I think, so the whole thing can be removed. I do it by cutting the harness right at the computer, and then pulling each of those wires out of the cab and back into the engine harness. Then find out where it goes and remove it.

As for plug & play, yes. But, the connectors aren't always easy to get apart after all these years, so take your time and do it carefully so you don't break something.

Having said that, the distributor has to be removed and replaced, and the timing adjusted. And that's not something everyone is capable of doing. The gear on the distributor is helical, so the shaft rotates as you pull the distributor up. And you need to get the new distributor back in the same spot so its rotor has to be pointing at the same spot when you start in as the old one's did when it came out. So, if this is Greek to you then you might want to hire this done. Give your mechanic the parts and he'll know what to do.

 

Don't forget the coil, Gary.

 

And BTW IIRC some 1984s are computer-controlled, Fonzie probably knows for sure.

 

I did forget the coil! Oops. Thanks for catching that.

As for computer control, by 1984 I believe all 2bbl 351W's in trucks under something like 8100 GVWR had a computer. (None of the 4bbl 351W's, the HO versions, had a computer.) The OP said he has an '84 F150 351W w/a 2bbl, so I'm pretty sure it has a computer, which is why I said his performance and MPG would be toast if he replaces the feedback carb w/a non-feedback unit.

 

For the harness, 1980-1983 Ford trucks and Broncos with the 5.8/351 2V engine is what you are looking for. Or, a 1984 - 1986 truck or Bronco with the 5.8 4V H.O. motor. Except for some California models, these had the Dura Spark II ignition system. And like Gary Lewis said, a 1980 - 1983 (and some early 1984) truck or Bronco with the 5.0/302 will work also.

Does your truck have a factory tachometer? If so, the Dura Spark harness will have a plug for the tach if the donor truck had a tach, so keep that in mind as well.

Here is a picture of the components you need to successfully make the conversion. When you remove the EEC-IV harness from your truck, the open plugs ("to Factory Wiring Harness") simply plugs into your truck's existing wire harness. The harness has plugs for the oil pressure and coolant temperature sending units as well, so there will be no need for any cutting or splicing:

 

Be aware of what transmission you have. If it's an AOD, an Autolite from a 60's Ford may not have the proper linkage for the transmission.