The Stovebolt Site Forums The Shop Area Engine Shop Dual carbs

I am new to this forum. Thanks for any advice in advance. I have a "52" 3100. Removed original 216 and am rebuilding a 235 out of a "55". I found matching Carter YF carbs and realize that a dual carb manifold for a "55" will have 2 15/16th bolt spacing for the carbs. The carbs I am using are 2 11/16th. In stead of ovualing the bolt holes in the carb, would it work to order a manifold for a "52", correct bolt spacing but smaller holes for the alignment spacers. I could either leave the spacers out or have the manifold machined to accept the larger size. This would look correct with the carbs mounted. Would I run into any other mounting or operating problems.
Thanks

If you're determined to run dual carbs, you've got the smaller-sized venturis which will work better. Not well- - - -just better. I'd suggest plugging the stud holes in the manifold, and moving them inboard to get the spacing correct for the smaller carbs. It's a pretty simple procedure with some creative setup in a drill press and a set of taps.
Jerry

X2 - keep that manifold, move the studs and use the smaller carbs.

I ran the smaller sized carbs that a buddy gave me that he'd just used a grinder and turned the hole into an open slot, fit either manifold. This set up worked fine for years.

Doesn’t it suck that no matter what method you choose none of them doesn’t involve machine work? If someone made adapters/spacers that rotated the carbs 90 degrees, reduced the carb B.H.C., blended the 2 diameters together and incorporated a pivoting linkage to tie it all together harmoniously they would have something. Either that or just put the smaller spacing on the repop manifolds.?

I am not really determined to run dual carbs, my reason is for looks only. Am I making a mistake?

Unless you do a lot of matching and synchronizing, and find the smallest-possible venturis on the dual carbs, you'll end up with way more venturi area than you need, and a really nasty bog at part throttle, backfiring, carburetor fires, etc. Dual carbs on a stovebolt are just eye candy. The engine was designed to run right on one carb, and adding another one of the same volume capacity without doubling the size of the engine makes no sense at all.
Jerry

Amazing!
Now if only Chevrolet had known that, they could have saved all that work on the Corvette.

Check out the 3-carb side draft setup for the 235 sometime. It's got only slightly higher volumetric capacity than a single Rochester 1-barrel for the same engine. I spent a great deal of time setting them up on Chris Craft marine applications, working for boaters back in the 1950's and 60's with more money that brains. The Graymarine flathead sixes based on the big Continental engine still outran them, no matter what they tried.
Jerry

Get a hold of Tom Langdon Langdons stovebolt engine company10am-7pm EST
586-739-9601

I'm sure if you call him,he will steer you in the right direction.


Tim

If its for looks and just cruising around, then go for it. Don't expect more power or fuel economy unless what you have really runs bad to start with. You may gain a little power and milage once you have tuned them a BUNCH.

I have tried three carbs on a 250, then two, and now back to one. I could make them all run OK, start just fine and look really cool. But at the end of the day, the one carb still does everything much easier. The two carb set up was using to stock Mono-jets, it should have been way over carbureted since one does a great job on its own. It started and ran really good, had more power but used more fuel. I didn't like the way it flooded the intake when shut off while the engine was warm. The evaporating fuel smell was awful for hours till everything was dried out. Leaning the out might solve the problem and I will try again when I find some jets and metering rods, but Mono-jet metering is not something you get easily.

Weather also changes the way they work, every time it got cold or hot, the engine would run different so I had to adjust them often. One carb seems to be able to handle change better, I haven't had the hood open since changing back to one.

It doesn't look nearly as cool, or run as fast, but it starts every time first time, gets decent milage, and doesn't stink the garage up.

Go ahead and set yours up and run it, it might be just what you want, if not, someone will want it, they always do !

Joe

Bart,
If all you want is looks, get a triple carb manifold and run dummy carbs on each end.

A triple with two dummies is something I never considered. If I am not happy with the duals that will be the next step. Thanks for all the advice.

Here are a couple of articles you might find useful:

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

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

Do it right and you will like the results. Using 2 (or 3) carbs you just happen to have might NOT give you the desired results.

A three-carb manifold with two dummies will not perform as well as a single carb set-up.

Jon.

I have several built inline sixes and all have multiple carburetors. One is an old 235 with a set of Holley-Weber's. Another has a set of Weber #36's on a Clifford manifold. That 261 engine is now in daily use, required no hassle with the original setup and the issues of synchronization almost disappear. Expensive but the horse power production is really impressive. The fuel mileage potential is much better also. Give serious thought to a good HEI too and off course good exhaust headers.
Normbc9

I read these articles prior to my search for a set up which is why I purchased these two Carters. I was ready to order the Carter-Weber carbs Tom Langdon sell when I found these two Carter YF's figuring they would work since they have the smaller base. I like the looks of the original style carb over the new Carter-Weber. I am ready to re-assemble the engine and think I will try these to see how it runs before I try anything different. I will be installing Fenton headers and HEI, left the original cam with hydrolic lifters. If I cant get her running to my liking I may look into the three carb setup with the two outside dummies. Again, thanks for the advice.