Technical 4 carb question

I've been told that when putting 4 carbs on a flathead that some or most people block off the front and rear carbs so only 2 are used. Is this correct?

 

You can but your manifold design will have to be right. Run all 4

 

Some manifold designs will permit ONLY running all four, and it works better anyway, if you have enough engine.

Jon.

 

I was wondering because I was looking at my triple and the center carb feeds all 8 intake ports and the front and rear each feed 4 so I got to wondering if on a 4x2 the center 2 would work the same way, feeding all 8 and the other 2 are just for extra dumping. Thanks for the replies.

 

If you want only three carburetors...buy a three carb. manifold, if you want to run only two carbs., run a...

Mike

 

Most 4 x 2 manifolds DO NOT share a common plenum, the ones I am familiar with either service the two cylinders the carb sits over or one carb venturi per intake port with balance tubes along the manifold. You need big displacement and no fear of higher rpms to really get the most out of it. Seems kind of wasteful and somewhat poser-ish to have the look without the performance, so there's that to consider too.

 

sold this one a couple years ago............. it was an Edelbrock unit

 

Most everyone that I know with more than two 2bbl carbs on a flattie say that it's too much carb for their engine unless it's a pretty serious build.

 

Are you sure? Just kidding, I remember hearing the same thing about 45+ years ago.
I've just started sniffing around for a 2 carb intake for a 8CM engine. There are a couple in the classifieds right now, but I'd like to find something closed. Sure are a lot of 3 & 4 carb intakes out there.
-Dave

 

There are also two basic types of flathead dual carb manifolds, "Regular" and "Super". The "Regular" has both carburetors biased towards the back of the manifold, allowing a stock generator to be run. A "Super" has one carb positioned directly over each group of four intake ports. Because of this, a stock generator cannot be run and a special offset generator bracket has to be used. Obviously, the "Super" has better fuel distribution and must be used with straight linkage. There are some who say that a regular can be run with progressive, but I personally don't think it's a good idea. One is a compromise, the other requires extra effort.

 

3 two bbls.with progressive linkage is the way to go. Remember 3 in a row, makes em go, 4 in a row makes em slow (unless you got a lot of engine)

 

Actually, the best setup is probably a small 4 BBL, but then you have to run a hood.

 

4 carbs are for alcohol and looks. the basic Flathead runs best with 2 carbs. JMO

 

Manifold design, tune of engine, carburetors selected, and the skill of the tuner are all going to play important parts in how well the engine runs.

That being said, assuming all of the above are considered; two or four will ALWAYS run better than three on an eight cylinder engine (physics - you can ignore it, but it will not ignore you).

Jon