I've had this carburetor and intake for a couple summers, $20 buy at Rhine beck the carb has a plate on it that says "Duplex improved carburetor, patented May 18, 1926, built exclusively for western auto supply co, by the Simmons mfg company Cleveland. Has a stamp on the carb that says pat 05-18-26, and next to that upside a number 91. The internals reveal a secondary gray flapper which I'm guessing is some sort of automatic choke/air restrictor that will help fuel flow. It also has heatint coil on the other side. Looks like a straight through deal for this carb. Is this a good carburetor worth rebuilding? It's all there. I noticed the needle is shorter than my NH. If it is a good carburetor worth rebuilding who should I send it too?

Secondly, the intake. It may just be a stock iron intake but I want to check. Has the Ford script, but also a Q mark on it.

From your description, it sounds like the Simmons we're used to, but I haven't seen one with a "Duplex" name on the tag. The Simmons carbs had their own name on some of them ("Simmons Super Power"), and the name "Wizard" on ones sold through Western Auto. Maybe the Duplex version was somehow improved from the Wizard. Anyway, the Simmons is a great carb, and certainly worth rebuilding. It's what I run on my car.

A picture or two wouldn't hurt.

I've got a few of them and love them. They perform well at speed and the flapper helps them idle. The same carb was sold under the names Wizard, Simmons, and Duplex. I even have one that has no name, just the patent numbers.

Is the intake stock? I've never seen a special intake for these carbs.

The Simmons Super Power carburetor was sold under at least three different names. The Simmons, the Wizard, and at least one (I think two) other names. They were marketed in many places, some of which preferred their own proprietary name on them.

They are very similar in design and pattern to a "straight-through" Holly NH. Some Holly NH parts can be used (sometimes some modification is required) for repairing the Simmons.
There are a few key differences. When repairing or preparing to use one. Check the secondary choke/flapper. Many of them were made out of a pot metal, and have self-destructed over the years. Many that are still hanging together are ready to fail. They are a counter-weighted flapper valve that helps control air flow through the venturi at lower speed/power conditions, allowing the straight through feature to operate at higher speeds with less trouble at low speeds.

The electric heater wire. Some of them had that. I have been told that some did not. I would not wire up the thing myself. It may have helped back in the day with the low quality fuels. However, modern gasoline is poor quality in different ways. It is much more volatile, and vaporizes if anything too quickly even without a pre-heater.
Frankly, I doubt that such a small loop of ni-chrome wire could transfer enough heat given the rate of air flow on the input to a carburetor to help much with fuel vaporization anyway.
Interestingly, it has been suggested that the air turbulence created by the wire loop may help the carburetor's efforts to atomize the fuel. I wouldn't bet on that either way. I would leave the wire in just to maintain originality, I just wouldn't use it.

I have always heard that these work very well. Almost a poor-man's OF. Maybe not quite. Someday, I hope to try one.

By the way, the intake manifold is a typical model T manifold from about 1919 through some of '26.

Thanks! Who would you guys suggest sending it off to for rebuild?

I have both an OF and a Simmons on the road today. The OF gives much better performance than the Simmons. The Simmons performs better than a NH. Good carbs. Matthew, rebuild it yourself. Just be sure to clean everything real good. Fun project.

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Except for special care with that secondary flapper choke, easy to work on. Rebuild it thine-self.
There was a fellow many years ago that was known for rebuilding these. He even made and offered reproduction flapper valves. Unfortunately, I do not remember his name, and haven't heard anything about him for maybe twenty years.
Is Russ Potter still around or doing rebuilds? (Shows how well I have been keeping up lately?) He is the only other one I know of. Stan Howe does fantastic work, but does not want to do iron carburetors in the first place, and has been overwhelmed with too much work to do lately besides.

I dont know for sure but the air bleed on the Simmons could have a turn in it but it might not, I don't know. If the hole went only in a straight line then the casting wouldn't need that little protrusion on the bottom part to allow room for another passage. There are 2 plugs in the top, one is for the stopper for the flapper and the other is just a plug. I was thinking where the drilled a vertical passage to meet the passage coming from the choke side then ending in the mixing chamber. The top of it was plugged the the hole in the top plugged. I don't know that for sure but you can see from the chalk marks in the pictures the passages drilled in the NH and the (maybe) 2 in the Simmons. If the passage in simmons is a straight line it would be easy to clean, if not and you can't blow air through it then it might be a little extra work. I never worked on the one I have because the flapper is missing.

That secondary passage in the Simmons would bring the end of the tube to the approximate same location as it opens up in the chamber as on the NH. Still just a guess.

I took the spray nozzle out, should've done that first, and looked and there is another passage. Since you can see the hole from the bottom you could clean it from there and not have to fool with the top plugs, they drilled from the top because they couldn't get a hole started from the bottom at such an angle very easy I guess.

Cleaned it up real good the other day using a foam cleaner, green scrubby then a tooth brush and kerosene, and had it sit 24 hours in kerosene. Used compressed air in all the ports and channels. Taped all the ports and inside section shut and hot it with a quick coat of paint just for looks. Going to give it new gaskets in the morning then try it out.

A float needle and seat for an NH will fit the Simmons carbs. The MTFCA carburetor book tells how to file and polish the groove out of the spray needle tip. Then you should be good to go.

Thank you for this information. I have one of these carbs. and was wondering about it. I may rebuild it and see how it runs. Again thanks.