Inliners International Forums General Discussion Hi Performance preferred carbs for 3x1 on a 292?

Hey gang, which carbs do you prefer for a triple carb setup?

I've got monojets, and also have Rochestor B series. They're all gonna need rebuilding. Wondering which ones to invest my time into?

What manifold do you have, and which flange pattern: 2-11/16" 2-15/16", or something else?

Its the offenhauser #5414, 3x1 for 230/250/292.

I think it is the larger flange for later carbs

IDK which is better between those 2, but there is certainly more data available for "B" installs.
That manifold comes with progressive linkage: idles on the center only to part throttle (cruising), then both end carbs open together, with all 3 reaching WOT simultaneously.
You should reach your cruising speed on only the center, which will vary depending on gearing, etc. Many linkages have some adjustment w/r/t proportions.
Gas mileage may be worse than stock because mixture distribution is not great (center carb is right on the #3-4 intake port), and varies with throttle position. Has anyone done any mods to the plenum floor to help (ditches, popsicle sticks, dams)?
Don't use small air cleaners, no matter how good they look!

To use two or three Rochester B carbs is a little bit of an exercise in patience. To get that kind of a set up to run really well requires a good bit of tinkering. Go on to our main site and find Pat Smith's outstanding article on how to set them up and you will see what I mean.

I generally had better luck using smaller carbs for like a 216 chevy (Carter YF for example) in a 2X1 or 3X1 set up.

Quite a few years ago now, Tom Langdon (before he retired from GM and before he took over Stovebolt Engine Co.) suggested that I try Ford Pinto Holley/Weber 5200 carbs. These are progressive two bbl carbs. Like a Q jet, small primaries, and progressive secondaries. I put them on my 235 and boy did they make a difference in drivability and clean spark plugs. I would think the same would be the case for a 3X2 install. You will need adapters and you will have to check hood clearance but you might consider those carbs. 1974 versions are the ones I use, those carbs have a threaded fuel inlet rather then the earlier brass nipple.

Thanks for the tips. I looked for the Pat Smith article, but could not find it. Can you post the link?

I've got 3 of each carb: Monojet or B, and extra parts of each also. I'm going to use one of these. I can't afford to spend several hundred bucks on webers. This is going in a '64 chevy van, and the 292 is already raising everything 1.5", so I don't have much hood clearance for anything higher than stock carbs.

Has anyone ever run monojets in a multiple carb setup? I'm currently running a single monojet on the 230 that is currently in my van, and it works pretty well.

With a 3 X 1, progressive linkage means that the engine's idle, low speed cruise, and part throttle acceleration will all be on the single center carburetor. IMHO the larger "B" (#3 flange) here is far more practical than it would be in a 2 X 1, where these ranges will use both carburetors simultaneously, and split the engine vacuum between them.
The next question is: how sure are you that you have 3 identical "B"s? There are 3 different throttle disc sizes with very similar appearance (1-9/16", 1-11/16",and 1-3/4") and 5 different venturis from 1-9/32” to 1-5/8”.
I suggest the smallest size at 130 CFM each @ 1.5 Hg" if you have a choice.