best carb options

[badkarma510]

Recently bought a 77 and had it all rebuilt. Guy at a performance shop talked me into a Holley 4412 carb and it runs like crap.

Here's whats been done on the build. stock 302 rebuilt with fireball cam, HEI distributor (from JBG), long tube headers (ceramic coated) rebuilt C4 transmission and all stock gears, Holley 4412, motorcraft ASF 42C plugs..... looking to return the carb and go to something else...... don't have the funds for EFI..... which carbs do the gurus recommend for this set up?

Rig will be a street queen so I am looking for daily driver performance and reliability. Thanks fellas.

 

[bronconut73]

The bad part about a Holley carb is all the adjustments you can make.
The good part about a Holley carb is all the adjustments you can make.
Hahaha.
Look on line or get you a Holley carb manual. I am sure all your new carb needs is some adjustment and possible re-jetting.

 

[badkarma510]

I've had a couple shops give it a try.... nothing. It runs kind of good, once it heats up it dies at stops and hard to start, plugs smell like gas...... do you think carb or something else?

 

[rguest3]

My favorite carb (2 Barrel) is the stock Autolite, especially for a daily driven truck. These carbs can be found in a little bit larger sizes as well for the mildly modified 302.

Holley's can be quite good as well if you can find a good mechanic who still knows how to work on carbs.

Regardless of what carb you install, put a 1/2-1" Phenolic spacer on first. Will help cure the hot starts.

Sounds like yours is running too rich.

 

[blubuckaroo]

That carburetor has huge venturis. It's made for circle track racing. Since you already have the 2bbl manifold, why not just find a stock Autolite or Motorcraft 2bbl?

 

[broncnaz]

Where's your stock carb? Id rebuild it and put it back on. To me that holley carb is a little big for a 302 but it should still run fine. It sounds like you may have a float level issue might be to high. There are other things that it could be like you may need a dash pot to keep the throttle plate from closing to quickly and stalling the engine out.

Theres not much else out there for 2v carbs that you will be able to exchange it for at your speed shop you might go with the 350cfm version the 7448 otherwise theres not a lot out there that I know about. A 350 cfm version would be better suited for a 302 and would have better lowend throttle response than the 500. Your stock carb would be fine.
I also have a feeling that that fireball cam may be a little to big for a street driven bronco so that can complicate the issue as well do you have any specs on the cam?

 

[SteveL]

Been there done that. I gave away the holley that was on my bronco years ago. For just street the edelbrock performers are great but suck off road. The carter afb is the same carb but cheaper. Dont think the carter is smog legal like the performer. If you're gonna wheel it get a q-jet.

 

[needabronco]

Before efi, I ran an Edelbrock 1826 Off Road Carb. It was very easy to setup and adjust, all it needed was a different set of rods and a choke adjustment. Once setup it ran great and was very reliable. My brother in law ran a Holley and it always needed adjusting and frankly was a POS off road. My Edelbrock carb never skipped a beat, where his was alway stalling, loading up, of flat would not idle when on the same trails...

If you don't want to run an Edelbrock I'd find a stock Motorcraft 2bbl, they really are the best carburator out there. They've been called the 'poor mans efi' for a reason!

 

[broncnaz]

Keep in mind guys a swap to a 4v intake and carb could run him another $500. Of course if he can scournge up a used manifold and trade his 2v in for a 4v it would be a wash. In that case for a street only machine a edelbrock 500 cfm 4v would be a good choice.

 

[rguest3]

badkarma510 - Do you know the Cam specs of the Fireball Cam? Is that the older Crane Cam that used to be popular?

If I remember correctly it's a fairly High Duration Cam (290'-294' Maybe) that you would probably NOT be happy with as a daily driver / street driven Bronco.

 

[Broncobowsher]

That 4412 isn't the greatest thing around. While it has a 500 CFM rating that is with 3" of vacuum. For all practical purposes it is the front half of a 750 CFM double pumper 4-barrel. Why the CFM discrepancy? The 4-barrel is rated at 1½" of vacuum. If you pull hard enough to get 3" of vacuum under that 750 4-barrel at full throttle you are really pulling 1,000 CFM of air.

Sounds like you have had a couple of places try to shadetree turn that carb. The only chance you have it a real tune. Get a holley tune book and a wide band O2 in the exhaust. It is tunable to make it run great, but you will probably have to touch every circuit in the carb multiple times to get it there.

Going to the stock motorcraft will do wonders.

Another thing I am looking at, with this engine build you state you are running stock gears. Since there were different gearing options available, what ratio do you really have? Most of the time the answer will be the 3.50 gears but not always. Next, what size tires are you running? The reason being is too tall of a tire for the gearing will make it drive like a dog regardless of what engine you have in it.

 

[nvrstuk]

Used 4bbl manifold should be less than a hundred bucks... get a rebuild Q-jet for a couple hundred and you're in great shape. Otherwise for street and mild trials the Edelbrock will work

 

[jckkys]

The 2100-2150 2bbl carbs are the best for street or off road. The 2bbl intake can remain intact and so can more of the money in your wallet. I have learned that speed shops aren't likely to recommend practical parts. They're going to push high RPM parts used for racing. The 4412 is for racing in bracket requiring a 2bbl carb. Low RPM where you do 99 percent of your driving, is handicapped. The original 2100 is rated at 287cfm and is the best choice for a stock engine. Crane's Fireball cams could have a 248 advertised duration, or a profile that's nearly a racing type. You need to find the specs on your cam. If your engine NEEDS more air flow 2100s go up to 351cfm.
If you come across a used or junk yard 4bbl intake in the future, then look at a 4bbl carb. The 500cfm AFBs, whether made by Carter or Edelbrock, are the easiest to tune and maintain on the street.