Anyone Run a Holley on Their 231?

I'm finishing up a stock refresh on my 231. It came with a Holley 4412-2 500 CFM 2bbl on an adapter plate. The jets are 76's, which I think are way too big. My Holley list says they should be 73's, which still seems fat for such a little engine.

The Jeep always ran rich with this set up. It also would start billowing nasty black smoke and stall out on long slow climbs. I have a variety of jets on hand. I have ordered a bowl vent extension to help with the climbing/stalling issue.

Does anyone have jet size info from their own Holley/231? I'm just looking for a starting point before putting the carb back together.

Thanks in advance for any info.

 

I ran a 2 barrel Holley on my 231 and I had nothing but frustration with it. Keep in mind, I am a diesel mechanic so carbs arent my thing. Anyway, when i got it to run good, it ran real good but not for long. switched to a carter and pretty much set i=on the manifold and forget it. I have not had to mess with it since

 

The usual suggestion in such cases is to get a small (1.08" venturi) Motorcraft 2100. Good off-road carb, easy to work on, fairly plentiful. Same base pattern as the Holley 2300. I have one on my 258 J-10. I ran the 500 cfm 2300 on my 304 CJ-5 for a while. made a big difference in power on the street, but just refused to run over rough terrain or at certain angles. Went back to the OEM 2100. IMO the 500 CFM Holley is way too much carburetor for a 231 anyway - fuel control will be lousy, and you'll have to set it rich to make it run right.

 

Go with the 1.08 2100.

 

^What they said. It's just too much carb for your engine, and the center pivot float bowl, while it's good for high performance use, gives poor fuel control off road. I like Tim's idea of the Motorcraft carb, or find a 4 barrel intake and a stock Quadrajet-both have the reputation as being good off road carbs.

 

Even though I'm no fan of Holley carbs, I'm kinda stuck with what I have for now. The only running issue I had before was the uphill stall. Other than that, besides constantly running fat, the Jeep performed fairly well with the Holley. The bowl vent extension should solve the uphill drowning issue.

If a 500 CFM 2bbl is too much carb for a 231, how would a Quadrajet be better? I was looking for a 2jet, but had little luck finding a non smog model.

 

Tapered metering rods. I have never had luck with 2 jet or Quadrajet off road, though. They flood at angles, IMHO.

 

According to my V6 Preformance book & my Holley book, the 231 needs a 390CFM carb...no more, no less. The Q-jet provides what the engine ask for. The metering rod and size biased primary-secoundary design is more sensitive to intake signal, which is less likely to over fuel the engine.

Look around on Ebay for a Holley 390 if you want to stay with Holley. Once you are sized correctly, tuning will be on the margins.

My 2 cents deposited.

 

A bowl vent extension may help some, but you're still gonna get flooding at angles-the fuel will pour in through the venturi boosters-I've seen it happen.
The Qjet is actually a bigger carb (there's a couple different versions but I think even the smaller ones are 780 CFM)
but it works because 90% of the time you're using the tiny primary venturis which provide better throttle response & fuel economy. The big secondaries use a spring loaded air valve which also controls the metering rods.

 

Actually, this is a good idea-find yourself a side pivot float bowl for a 2 barrel and get a spring loaded needle & seat. That should help quite a bit and it shouldn't cost too much if you can find a used one.

 

Thanks for all the input fellas.

Like I said earlier, I'm stuck with this one right now. I think I'm going to throw some 68 jets in it and give it a go. I will start exploring other options soon.

 

Not much help here but, I run a Holley that I took off my old Scout. It was a 266 V8. I don't know what cfm it is but, I figured if was good on that 266 (and it was) then it would work on my 231. I have good luck with it so far, both on and off road. I'm sort of embarrassed that I don't know more about it. I got sick of 2g and threw this Holley on, on a whim, and it's been doing well. I'm not much of carb guy. I should learn more about them, or atleast about mine.

 

I wouldn't stay stuck with that too long. The problem is you're never going to get a good venturi signal with such a large primaries on a small cid engine. 2bbl carbs can be had for cheap - everyone thinks they NEED a 4bbl upgrade. Might even be able to trade that 500.

 

I have this carb on my jeep and I have read about an "off road" kit that utilizes a spring on the float. Do you or anyone know of this kit? Carb works great and I would highly recommend it but I get a stumble on downhill descents and I'm pretty sure it's the float jostling up and down and dumping extra fuel in.
Alan

 

You want a spring loaded needle and seat, and the side pivot float bowl. I don't know if Holley supplies this as a kit. they list an "off road" needle and seat which appears to contain a spring: http://holley.com/6-513.asp and http://holley.com/34-7.asp This is probably what you need. If you have a center pivot float, you also want a side-pivot float and bowl, probably this one: http://holley.com/134-281.asp - you'll need to check that the transfer tube hole can be plugged (or comes plugged) and that the adjustable "off road" needle and seat is compatible with this bowl. (A used bowl and float from a junk carb is another option - I've found that parts from ancient Holleys fit the newer carbs just fine.)

I would also raise the bowl vents, and fit either the vent screen http://holley.com/26-39.asp or the vent whistle http://holley.com/26-89.asp to slow down sloshing from the bowl into the carb throat. I've also seen jet baffles soldered to the main jets - pieces of brass tubing that extend into the bowl.

All this aftermarket stuff can add up ... you may be better off to find a used 2100 or 2150. They do not have the fuel control issues that the Holleys have, and generally work well on the trail without any mods. The Jeep 21XXs after 1973 will have a float damping spring on the float pivot - if you find a carb with that spring, hang on to the spring.

 

I wasn't clear with what I said and after rereading it, I see why. My bad.
This is the carb I have now on my 225, (1.08" venturi) Motorcraft 2100.

 

The only float damping spring for a 2100 that I know of is the factory spring that came with Jeep carburetors. If you go to a Jeep junkyard and open a bunch of carburetors, you might find one. In my experience, the rebuilders throw them away, so you need to find a carb that has not been professionally rebuilt.

If you can't find the spring, you could try lowering the bowl level some. This will lean out the mixture some. I would just run it with the lower level and check the plugs. If the plugs show too lean, you can go to a step or two larger main jets. Motorcraft jets should still be available - though the source I used to get mine has quit the business.

FLASH - there is an aftermarket source for the spring. I looked for Motorcraft jets and found this: http://www.carburetion.com/ford2v.htm

 

:tea: