The Stovebolt Site Forums The Shop Area Engine Shop two or three carb set-up ???

Guys, if I wanted to run two or three carbs on my 235, What modifications do I need to do ? Besides a manifold, do I have to do anything else.

You might wish to give this venture quite a bit of thought before you plunge into it.

Bolting on 2 or 3 carbs will look good, but unless some engine modifications are done, will not improve (and could make worse) engine performance.

Typical mods might include better exhaust, a different camshaft, ignition changes. More serious mods would include compression, and some lower end work.

Choosing carburetors to fit the particular tune of your engine will give much better results than simply throwing on some carbs.

Using two carbs means running simultaneously. This system gives excellent results, but is more difficult to initially tune (once tuned, should be bullet-proof).

Three carbs may be run simultaneously; or as a primary (center) and two secondary (ends). Easier to initially tune, but worse performance than 2 carbs unless you get serious with other engine mods.

Jon.

Thats what I thought Jon. Thanks for the advice. I'll stick to exhaust and ignition box(s).

Thanks, Jason

Easy Jason, not so quick. There is another way to gain good twin carb performance. Use the Weber style 2 bbl which have a secondary built into them. I think this is a much better way to gain both power and economy w/o going to the "hard to tune" 3-5 carbs you see in books. The internal upfits should also be done of course to take advantage of the increased fuel mixture. Probably the easiest thing you can do is put on a dual exhaust manifold. You fail to mention what engine you have. You'd be surprised what can be obtained from an old inline 6. If yours could use an overhaul anyway then it makes sense to upgrade in "innerds".

Again thanks for the input. I have a 235. Really clean engine. Doesn't even leak oil, which surprised me. I just adjusted the valves, and she runs really good. Also, a complete tune-up has been performed. I really like working on this engine, very simple. Not like the trucks I work on at work. this engine is sitting in 1 1/2 ton stakebody. (1956) I've just been reading a lot about these dual set-ups and was wondering how it works. I am however looking for more "gusto" from my motor though. I've seen custom exhaust manifolds, intakes, headers, etc. I was going to get a dual exhaust manifold but then I read about guys "grinding" them to fit. Pretty liery about that. Anyway, this site is great. A lot of talent and knowledge here. Also, the guys here are more than willing to share to "newbies". Not like other sites when they won't respond cause you ain't in their click. Again, thanks.

Just curious about more power----Jason

I'll play the flip side of the record.

These trucks were built with fuel economy in mind. Remember the time frame, WWII had just ended, Korea was in the picture. GM intentionally undercarbed the 216/235, so as not to waste gasoline.

More carb will raise your performance on a stock 235. I can't say by how much, but some. If you do go with duals on a stock 235, you will probably need to rejet some to lean out the mixture.

Another good way to improve your performance is to change the exhaust to a split exhaust manifold, either with headers or by having a stock manifold split and welded. Kansas Kustoms does this.
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