First things first, a photo of what I'm working with under the hood. This is a 4.9L 300 i6, in a 1986 Bronco. I've got the feedback system, but also the big air cleaner assembly. See below:




I've read quite a bit about removing my feedback carb, and going to an HEI distributor. A good number of threads out there and videos that I can follow.

But can someone tell me about this clunky fresh air tube and associated assembly parts? Was this something needed in a cold climate region of the US? This is now a Texas based Bronco, and we just dont get much cold. Additionally, I dont have to pass any emissions testing to keep this 86 on the road.

So what all can I rip out to simplify things under the hood? I see a lot of photos of 4.9L 300's without all the air tube stuff.

Point me in the right direction please!

 

The reason why see then with out the factory air filter and "fresh air hose" is people rip it off the throw it away, not a good thing.

Dont think if it as not needed because it dose not get cold (just yet) but as a cold air inlet.
Cool / cold air makes power as id is denser so you can add more fuel = more power.

In summer lets say the temp outside is 90*f what do you think the under hood tamp is?
A he11 of a lot hotter than 90*f for sure.
Hot air in the carb = less power and you can then get pining.

If it was me I would keep that factory air filter in place and hooked up just the way it is.
The flapper in the snorkel should pull warm air from the exh manifold when the motor is first started and is cold.
It keeps the temp going to the carb at the "right temp" for faster heat up and better running when the motor is cold.
It also helps when it is cool / cold out and the carb from icing.

My truck is a 81 but run the factory air filter assy. and fresh air inlet as I want to pull in cool air in the summer time as it gets to mid 90's ti 100* here.
I also drive the truck in the winter and had it out when it was in the low 20's.
Be it 20's or 90's I can fire it up back it out of the garage, put the seat belt on and drive off.
With the choke set right and the fresh air / hot air working I can do that.
Sorry I dont have a picture of under hood of mine, I need to get one some day.
I also have the tear drop type air filter assy.
Dave ----

 

It looks like you are running after market AC who's kit is it?
Did the truck start as a factory AC truck or dealer installed AC or none at all?
What dose the dash / vents look like?
Dave ----

 

That's looks VERY clean for a ECC-IV feedback carb engine. Can I buy some of the parts off you if you decide to convert it? I'm in CA so I can't remove parts.

 

Vintage Air. Its their brand new version. It blows colder than my daily driver Kia SUV. Incredible piece of equipment. And yes, I can get some photos of the dash with the vents.

Was installed by a vintage auto shop. They did a killer job. Not cheap, but it was a non AC truck, and that wasn't going to fly in TX.

 

Yep, we can chat about it. Yes, the carb is super new. Like maybe 3mo old. Probably less than 10 running hours on it.

I'm pretty sure I'm going to convert, bc I get crap for power on the highway. Likely stuck in some kind of limp mode or something, very similar to the woes of a lot of the guys who rip out the feedback system for HEI/Duraspark II

 

Thanks Dave. Good explanation as to why some folks keep the factory air assembly.

Sounds like its not having any adverse affect on my trucks performance, and most likely the feedback system remains the biggest culprit.

 

Before you send away for your membership kit in the "Rip Out All That Pollution Crap" club (new members get a genuine imitation bronze-plated belt buckle!), please peruse this thread for my over-inflated opinion on factory snorkel intakes:

https://www.ford-trucks.com/forums/1...nt-filter.html


At the very minimum, plan to upgrade your windshield wipers as detailed at the link. Safety first!

For the actual removal of components under the hood, this instructional video shows how it's typically done, often right before the vehicle gets sold. The subject is a jet engine, but the same principle applies to any motor:

 

What size tires are you running? We've seen the situation many times where oversized tires are installed, which makes the engine work a lot harder. The poor engine gets blamed when there may not be anything wrong with it, other than being asked to deliver more power than it was ever designed to do.

 

31's on stock rims, stock sized shocks.

Only thing not stock on this truck is the Vintage Air system.

I've battled poor highway power for a while. Tried throwing parts at a lot of stuff (fuel delivery, filters, etc) before stumbling across info on the feedback carb.

Is it really this easy?:

 

Yes, it can be easy. You need to pay attention to details though. Have you ever swapped a distributor out? Once you bolt the new carb in place you may have to do some modifications to make the throttle cable hook up to the new carb.

 

I had to pull the current distributor in order to change out the ICM when it crapped the bed and left me stranded. I'll probably need a timing light this go around, unless there are some other tools that you'd suggest for this job - tuning things with the new non-feed carb and HEI dist.

 

Thanks. I hate living here but for now I have no choice.

If you need to get it running better for the short term, do a code scan. There are three tests; engine off key on, engine off continuous memory, engine on. Engine on is a little more tricky because you have to brake, steer and throttle it at the correct time. It's really not that hard at all. It will tell you a lot.

I had a lean code and it was the front intake bolt came loose. Also, the smog guy turned the idle mixture screw in a little far. Weird crap on these models. Computer controls mixture yet it still has a mixture screw. Mine runs really well but I'm sure it could be better if I was able to hand tune.

 

I read an article a while back about HEI distributors. The GM version they said had a designated position for the #1 cylinder, but as long as the firing order was correct the position didn't matter. It sounded weird to me because I'm an old point and condenser guy.

 

You can put the distributor in any position. But you need to make sure you have enough swing to get the timing set, The HEI unit is large in diameter, so you need to be careful with this. And the sparkplug wires fit better if the dist is in certain positions more than others.