1986 4.9 carb and distributor change

Hi F150 owners!
First off, thank you Gary for creating this resource! I have learned so much from all of you guys.

I have a 1986 4.9 F150, I have owned it for about 10 years, and use it as my "dump" truck (mostly taking yard waste to the dump). I want to keep it alive just for that purpose. It is rusting out, and the engine electrical connections are getting corroded (I live in Hawaii), and that has been causing all kinds of problems with the ignition and smog component wiring and connections.
Since we don't have a smog check in Hawaii, I decided to simplify the system.
A few years ago I put in an HEI distributor (the blue cap version), that helped a lot.
Just recently the carb started running really rich, and fouling the spark plugs.
I tried to lean it out but that didn't help.
I decided to turn it into a "pre-smog" engine (the air injection and A/C was removed by the previous owner) as much as possible.

From some of the posts here (and on the F150 website) I learned that a basic YFA carb would work, so I ordered one from Amazon and put it in.

So far the truck is running great! I was an easy job, the only glitch was that the aircleaner bolt threads were smaller than the stock bolt, so I took the support off and tapped it to 1/4-20.

Here it is, just finishing it up... (I will add more pics, with comments under this post)

Paul

Good job, Paul!  Yes, a simple carb and ignition make for a reliable engine.  And while many on here dis the HEI, it is simple and powerful if given enough current to do its job.

Looking good!  

Here are the pics I took during the job.

Before




Carb removed, you can see the EGR plate, the vacuum ports and the transmission kick-down

Here are a couple of Youtube videos, if you are interested in seeing it running.
(No, I do not monetize any videos that I post, I only post them to help others, just as others have helped me)

First time started:
https://youtu.be/aABqOwHeUds

After some simple adjustments:
https://youtu.be/NL3HciugeCs

You did make quite a difference in the way it runs.

But the hose off the front of the carb is a bowl vent, and is normally routed to the charcoal cannister that sits below the battery and collects fumes from the carb and the tank when the engine is off.  Then when the engine is on a low vacuum sucks the fumes out and burns them.

However, you shouldn't have the bowl vent connected to vacuum itself.  The bowl of a carb is to have atmospheric pressure on it, and if you put a vacuum on it that will change the air/fuel ratio the carb provides.

Next up is the power to your HEI.  You don't have enough current going to it, and too small of wire.  Yes, you have 12v but power is voltage times current and you don't have enough current going to the distributor.  HEI's are power-hungry devices and GM learned the hard way they need lots thereof.  Go to the page at Documentation/Electrical/Ignition and then the Ignition Simplification tab followed by the One Wire tab to see a recommended way of wiring it.

But you have it running well.  Maybe it can be just a bit better?  

Thank you Gary!

I will make those changes.

Paul

That carb looks like a feedback carb with a block off plate.

Looks strange to me. I wonder what Carburetor calibration code the manufacturers copied from?

I also wonder if you could put a feedback solenoid on it, in place of the block off plate?

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I've got three old feedback 1BBL carbs, two Carter and one Webber for parts in rebuilding one good one.
It would be nice if we could get new ones for us in California.


Looks like a good install. I agree with Gary that the evaporative emissions and PCV valve controls should remain working. One is good for the engine (PCV), and the other is good for the wallet by controlling fuel evaporation.  

Does your carb have a kickdown adjustment screw on it? If so, what did you do to adjust the kickdown rod? Did you adjust the screws together or remove one of them? Thanks CJ

This is great. I did an HEI conversion on a 82 300 I6. You need to follow Garys advice on hooking it up properly. Run the switched 12V to a relay, have the relay then run full power directly from the battery with a heavy guage wire to power that HEI. It'll last longer and run better.

In your video you tell us to tell you what to do with that float bowl vent, but you have the comments section turned off on your video.