The Stovebolt Site Forums The Shop Area Engine Shop Carburetor Recommendations

I am looking for a new carburetor in the next couple of months.

My engine is a 235, 3 speed tranny, and stock rear end. Im wondering if I should install a dual carb or single, 2 or 4 barrel? Pros Cons?

Smart folks on here have pointed out the following:
1, Multiple Carbs are mostly eye candy.
2, With too large a venturi the airspeed needed to run the low speed circuit will suffer.
3, Low speed circuit will go lean, and changes to fix that will eat fuel.
3, Normal drivability will suffer.
4, Two small carbs might suffer less.
5, Balancing multiple carbs is a PITA (translation available in lots of places).
6, None of the above applies to modified engines.
7, You might want to do this any way.
8, All of the above applies to both 2 and 4 barrel carbs except the "balance" thing. And you can still get that messed up with any 2 or 4 barrel carb.
9, Did I mention that you might want to do this any way?
In the good old days, Hot rodders had limited choices, and what they did involved more compromise than most of us still around care to remember. You can get more power from these Inline 6 engines. Not, however as much as a SBC. Keep in mind that a stock 350 in 1971 was rated at...165 HP. Our 235 was rated at close to 140 or a bit less. Now to me that sounds pretty good. 100+ cubic inches equals 25 HP? Now my 6 sounds better, and better. To get close to say 165 HP, call Clifford, and Speedway. They will help you spend some money. I did say you might want to do this anyway? I am thinking about the 2 carb idea my self. And still have not decided which carbs to run. There are folks that know and some are on this site. I think (warning, opinion ahead) that 2 smaller carbs, with a cam and new lifters and a small runner intake (like Offenhauser) might give me a drivable truck with a modest improvement in HP. And I like the look, a lot. How much money will this cost me? 600-800 dollars. And that is just the big parts. Little stuff will I expect add up to another 200 dollars...might be why it is still in the idea stage. But 160 HP and a great look...well that is why I am still thinking and planning. Welcome to the club of unfilled expectations. Enjoy.

I'm thinking in 1971 that was net HP. Back in the 235 day, that was rated as gross HP.

OK so apples and oranges...Bare engine, without a genny or a muffler for gross and the same with all that stuff hooked up is net. Change over was in the late 60's and early 70's. And... no conversion formula.So best guess? 235 would make about what 115 hp? and the small block would still be about 165? That sounds about right. I would also think that advertised HP from the 60's would be somewhat suspect. Advertisers are known the world over for their honesty. Any way about 25 HP for accessory and muffler would be a good working guess. Thanks for the information. I was aware that SAE and DIN were different and now I have this as well. The new way to rate engines is in kilowatts and that is a whole "nuther animal. Still a base line from stock to modified with natural aspiration with a gain of 18 percent would seem achievable. That would give 140 HP gross to 165 HP gross for a 235. Seems that could be done with out loosing drivability. Now about that 350 HP small block? You gotta love it don't ya?

I would call Tom Landgon from Langdons stovebolt co.

He has a Carter Weber carb that works well for dual carb engines (from what I hear and read). He also has other modifications and a TON of knowledge about these inline 6's

Worked with Tom while he was at GM. Great guy!

The dual Carter-Weber carbs that Tom sells seem to be very nicely matched to a 235. His linkage kit is excellent. I bought very nice looking converted oil-bath air cleaners from Tom.

If you use the Fenton dual intake with 2-barrel to 1-barrel adapters, and you use Fenton headers, no grinding/adaptations need to be done on the manifolds.

Those posts above are of Langdon's Carter-Weber set-up on a 261. I found that they are too small for a 261 (which is over-bored to 270). However, they were very reliable and smooth.

I have changed from dual carbs to a GMC 270/302 GMC engine's single carb on my 261 (I think this would be too much carb for a 235).

If you do not care about the eye-appeal of dual-carbs, and want simplicity, reliability, and a little better performance, you might want to consider a Zenith from a GMC 248 or maybe 270.

Tom Landon likes to heat the intake manifold with cooling system fluid. I prefer the simpler exhaust manifold heat pipes. As far as I could feel, they both do the job (with the exhaust-gas heating method maybe being smoother at cold engine start-up).

I have a 235 in a 54 Burb that runs good and is in the what if stage but a 51 that's getting the LS1 5.3 4L60E treatment. So I guess I'll see how all that washes out. But I was thinking as to multi carb's what about the Corvette style set up. Did those engines have mixture issues??

If you are thinking of multiple carbs, these articles might give you some food for thought:

http://www.thecarburetorshop.com/Dual1barrelcarbs.htm

http://www.thecarburetorshop.com/Triple1barrels.htm

http://www.thecarburetorshop.com/CarterChevroletW1.htm

Jon.