Guess what?! Jegs has a Offy DP Kit...and inside the kit is a Mr. Gasket #720-260. It looks like it's one continuous gasket. problem solved!

 

so you kept your stock intake manifold, got a 2-1 carb reducer kit? what carb did you get? i'm wanting to do the same thing without having to by a new intake manifold. but i am going to be getting the hedman headers though. that's a must.

 

Like these?


Walker makes a large diameter Y-pipe that helps quite a bit with stock manifolds.



Compared to stock.

 

Diggin' this one up...

I'm doing the 2100 carb upgrade and need to buy the adapter. My carb only has 2 bolts for the 1bbl to mount to the intake and the adapters look like they have 4 bolts. Any suggestions?

Photo Gallery

Trans-Dapt Performance Products 2025 - Trans-Dapt Performance Carburetor Adapters - Overview - SummitRacing.com

 

Walker makes a large diameter Y-pipe that helps quite a bit with stock manifolds.



Compared to stock.

[/quote]

Would you have the Walker P/N for the Y pipe? I can't - quite - see it in your pic.

 

Don't use a 2-1 carburetor adapter. It's a poor way of doing things that will result in a poor-quality upgrade and you won't be able to get it to run as good as you could if it was going on a 2bbl intake.

If you want to adapt to just a 2bbl carburetor, pull the intake and exhaust out at the same time, take them both (still bolted together, now) to a machinist and have him machine the top of the intake manifold where the 1bbl sits to accept a 2bbl carburetor. Then, have him plane the side of both manifolds (while they're bolted together) to make sure that you can get an even seal along the head when you torque it back down.

The truck will run much better this way.

EDIT:

From classic inlines:

http://classicinlines.com/logmods.asp

"Upgrading to a two barrel carb over the one barrel definitely offers improved performance. However, when using a two into one (2-1) type adaptor, the air flow is funneled into the log intake through the existing one barrel opening. This limits the full potential of a two barrel carburetor, and if the carb is to large for the application, there's a good chance it will suffer from hesitation and flat spots coming off idle and under acceleration."

"The conversion method offers substantial increases in power and torque, over the two to one (2-1) type carb adaptors, which was quite evident when we did our dyno testing last summer."

Scroll down to the 2V conversion section to read relevant info.

On a 300, you won't have to remove the head or do anything funky like that (the article is mainly on 200s and 250's). You can get away with having it machined for a 2bbl carburetor a lot easier.

 

...Not my pic.

P/N 45166
Use an 1 7/8" hole saw to clean out the short side of the Y.

Josiah has some sound clips on his YouTube channel
jthorngate3 - YouTube

 

Thanks! I've been wanting to adopt the efi exhaust manifolds but really wanted to stay with a better flowing single exhaust on my '85 4wd.

I'll start collecting parts with this and some good manifolds as the first items.

 

Thanks for the advice on the intake. Im gonna call my machinist today and get a quote. As for the 2-1 adapter, Ive yet to find one that actually fits the Autolite 2100. The above mentioned both are too small on the 2 bbl side. The closest I got was the Trans-Dapt TRD-2041. Summit sells it for $48. The throttle linkage side needs to be notched for clearance and the same for where it sits above the accel pump. Kinda jenky, but will work for anyone wanting to go that route and on a budget.

 

Finished the 1 bbl to 2 bbl conversion last night. The Autolite 2 bbl carb wont fit on a 1 bbl intake no matter how you orientate it. Not enough real estate! If anyone needs step by step help, lemme know cuz it was a pain having to figure it out as I went. I just need to fab a bracket for the throttle cable and we're done.

 

It looks good! Hopefully it will also run well! Keep us posted on how it goes.

I have some decisions to make on mine - it has the feedback carb setup so for now I'm trying to get it to run/idle well. My engine has old, hard vac lines which I intend to replace + connectors, but the worse problem is it's just tired with some blowback.

I may be interested in doing something similar to what you did later of as I collect parts for a DII conversion and sort out the issues I have now.

 

I am interested in how this turns out! Subscribing!

 

Your question is one of the the most common/best to up grade the I6. Having plowed this ground previously, my solution for the exhaust was to update the "Lincon log" exhaust manifold with a latter 80's OEM F150 dual manifold and down pipe (with cat.). Big difference. A little grinding on the manifolds is required for proper mounting. The hot air tube for the choke needs to be tapped into the manifold and the shield for hot air to the carb. modified. Second, my experience with the 1bbl feedback carb. was it's not rebuildable when necessary (several shops in a majior metro. area) . Instead, an Offy. 4bbl. intake and a 500 cfm carb. were readily available. CJ fans have dealt with this issue also. Whatever iteration you choose it's a hugh improvement over stock. Can't address emissions in your area - worked in mine.

 

So the 2 bbl conversion is a success. The Bronco runs a lot better, way more power (compared to tired old 1 bbl). Throttle response is snappier, and she pulls off the line quicker. I havent run it enough to calc mpg, but I will through the next tank of fuel. A lot of old components were taken out and under the hood is a lot cleaner. There were many wire harnnesses that were not connected nor was there another connection for it. Many frayed, rotten wires, some melted together. I feel much more comfortable driving my Bronco now than ever.

Here's what was accomplished:

2 bbl Autolite 2100 carb with 2-1 adapter
Removal of computer controlled/feedback carb
Removal of old ignition system
Removal of ALL smog components
DSII dizzy installed
GM HEI ignition module installed
Same Motorcraft coil

My next plan is to get some EFI exhaust manifolds or headers. Removing the old exhaust and cats should help wake this ole girl up!!

 

Did you go with the Trans-Dapt TRD-2041 adapter?