Inliners International Forums General Discussion Engines offy 3x1 on chevy 292, use rochestor B or monojets?

Hey gang,

Like to get your opinions about which would be better for a offenhauser triple carb setup on a 292:

3 Rochestor B's or 3 monojets?

Its basically a street toy / daily driver. Engine & head is stock with headers/dual exhaust. Considering a mild cam upgrade

I have a good supply of both B and monojets sitting on the shelf. Once I decide, I will rebuild 3 of them. Just wondering if anyone has opinions about if one model is better than the other for multiple carb setups? Linkage will be progressive with center primary, opening first, then front and back opening together acting as 'secondaries'

Both!
This is on my list to try, and compare to the 4bbl setups in a shootout. Havent done it yet.

I prefer the "B" over the "MV" carbs any day, but I suppose I'd try a set of each to see how much better/faster they were vs each other.

Also depends on the sizes - the "B" carbs come in about 5 different sizes - 3 of the big ones is about like running a 550 Holley 4bbl. 3 of the common (194/230cid) middle size "B" carbs makes about 420cfm at 1.5" Hg, about enough for 200-240hp which should be about what you make with the cam. Depends how much CFM you need.

I believe the monojets are cheaper than the B models. Never have bought a reman B model. I bought a monojet for a late 292 I have and haven't had issues yet.

Duececoupe, what specifically do you prefer about the older style B carbs?

I will take a guess and say that my carbs are most likely the average middle size. My cam is currently stock, if I upgrade it will be a mild upgrade, nothing big. The head will remain stock, and this is for a street car, not racing. So smaller carbs are fine with me. 420 cfm is plenty for what I'm doing.

Cost of the carbs doesn't really matter, since I've already got 3 of both carbs on the shelf here. Would be cool to try both, but labor to build 6 carbs is alot, - ugh!

Well here is what I think I know about the B, BC, BV carbs.
I have also guesstimated their CFM at 1.5" Hg (the way most 4bbls are rated - so to guess the CFM you need, just "double your horsepower and subtract 10%", that formula works pretty good).

Easiest way to tell which "B" you have is measure the throttle bore, that narrows it down usually, then take it apart for detail. The "B" carbs are just SO easy to rebuild and work on, I guess that's why I like em.

"Old" means the old early-mid 50s style choke. "New" means the 60s Nova/Chevelle style choke.

Corrections welcome!


8 is enough! The :"B" carbs Estimated
carb venturi throttle choke CFM CID Used On
b1 1-1/32 1-1/2 new 86 CID=235 econo truck 60-62
b2 1-7/32 1-1/2 old 122 CID=216 50-53
b3 1-3/16 1-9/16 old 123 CID=235 50-51
b4 1-9/32 1-9/16 old 136 CID=?
b5 1-11/32 1-9/16 new 140 CID=235 52-56, 194, 230/140
b6 1-15/32 1-11/16 new 168 CID=261truck
b7 1-9/16 1-3/4 new 185 CID=292truck, 230/155HiPo
b8 1-5/8 1-3/4 old 178 CID=261truck

PERSONALLY I USE HOLLEY MODEL 1920 1 BBL CARBS WITH MANUEL CHOKE IN CENTER CARB. TAKES ALOT OF ENGINE MODS TO RUN 3 CARBS AND IT WILL SUCK THE GAS PROMISS.