2x2 carb setup

rick r

rick r

Senior Member
Helping a friend. He has a vintage thikstrom (not sure if this is the correct spelling) 2 carb hi rise manifold. Question 1, will this manifold work with one carb with a block plate under the other one, if so is it better to run on the front carb or the rear carb. Question 2, which are the best carbs to run on a 2 carb setup, holly 94s or stromberg 97s, stock 8ba with finned heads.
 
I dont think a 2 carb manifold is going to work very well with either one blocked off. As far as carbs go ,I have always used Strombergs on multicarb applications so I cant speak for the 94s.
 
I don't know about the Thickstun, but on my Edelbrock Regular (very much like the Thickstun), it will not run well on one carb. Either Strombergs or 94's will work. I prefer 94's
 
On a stock motor the 94's will probably run better. If you must go to a single carb, get a one carb manifold. The motor will be much happier and you won't drive yourself nuts trying to tune a dual carb manifold for a single pot.
 
Why does he want to run one carb? If the reason is the perceived notion that running two carbies is more fuel expensive than one, he is misinformed. A dual carb system can (and should) be set-up in such a way that not only is performance improved with a slightly peppier engine, but also with correct jetting etc the carburetors working in tandem actually use about 5% less fuel than a single carb. Surely that's one of the best win-win situations a Flathead can have.

From memory the Thickstun manifold has the risers close together, this is not the ideal configuration as the flow tests indicate the best fuel/performance efficiencies are achieved when the risers are located over the engine ports. However, while the Thickstun may not achieve 5% efficiency it won't be too far off.

As for appearances, that is in the eye of the beholder. A Thicktun manifold is a highly desirable piece of equipment, and I really like the 'look' of the carbs mounted backwards.
I'm pretty sure I would cringe if I were to look inside your friends engine bay and look at the travesty of one forlorn and lonely looking carb sitting on a manifold built for two.
 
If he wants just the look, he could use an Edelbrock Slingshot manifold. It runs great on one carb, or set the carbs to run progressive, like a single 4-barrel carb. Since both carbs dump into the center, all cylinders are fed evenly either way.
 
I set up an Offenhauser (regular dual) with progressive 94s and it works well. With progressive linkage it runs on one carb until about 75% throttle.

For all the talk about even feeding, a carb guy once told me to look at an inline six and see the difference in lengths of the manifold runners. If unequal runner length was a problem, then there would never have been a six cylinder manifold with one carb in the middle.
 
If just for looks, trade the Thickstun for a 3X2. Run a shim block off under 1 and 3. Get a flow thru fuel inlet adapter for #3 and put a screw in it to block the fuel. Do the same to the end inlet adapter on #1. Dress it all up with progressive linkage and no one will be the wiser as you run off only the center carb.
 
36tbird said:
If just for looks, trade the Thickstun for a 3X2. Run a shim block off under 1 and 3. Get a flow thru fuel inlet adapter for #3 and put a screw in it to block the fuel. Do the same to the end inlet adapter on #1. Dress it all up with progressive linkage and no one will be the wiser as you run off only the center carb.
Click to expand...
Until the carb in the middle starts showing gas stains! :D
 
2- 81's on a stock engine seem to be the ticket. 2-97's or 94's with smaller jets in them like 44's or '46's for the 94. Stiff power valves in them as well. I run 94's because that's what I have and they work great. My friends run 97's and we all have similar luck.


Enjoy it makes a whole different car out of them.

Tim
 
Gentlemen I think we've 'been had'.
Why, if the 'friend' only wanted to run one carburator doesn't he simply use the original manifold?
Is our 'friend' rick r priming the pump for the sale of a Thickstrum manifold?
Why no feedback from our friend, or thanks for our comments and advise?
I thick our 'friend' is sittin' back with his feet up, having a laugh at us and his immaginary friend.
 
Mike51Merc said:
....

For all the talk about even feeding, a carb guy once told me to look at an inline six and see the difference in lengths of the manifold runners. If unequal runner length was a problem, then there would never have been a six cylinder manifold with one carb in the middle.
Click to expand...

Straight 6 cyl engines are notorious for uneven fuel distribution. End cylinders, especially the front, run too lean. Case in point: Buick went to the trouble and expense of using dual carbs on their straight 8 in the 1940s.
 
Fe26 I'm sure there are many who post answers here whom have not gotten a thanks, or for that matter any kind of response. That's the way with some folks, so be it. To suggest anything more as an ulterior motive is pure conjecture; the gentleman may be otherwise involved, (maybe even working!) there is simply no way to know.
I don't think there would be any need to "prime the pump" to sell a rare Thickstun, Tommy T. died at an early age and it's a rare, low volume piece. Oh, and BTW, it's the Hexagon with the rear facing carbs.
 
To FE26, sorry for the late reply, I have been away for a few days. As always I appreciate the help I receive from fordbarn. My bfriend does not have a computer or access to fordbarn, and NO his Thickstrom manifold is NOT for sale at any price. It seems that I have some how rubbed you the wrong way, for that I appologize.
 
rick r said:
To FE26, sorry for the late reply, I have been away for a few days. As always I appreciate the help I receive from fordbarn. My bfriend does not have a computer or access to fordbarn, and NO his Thickstrom manifold is NOT for sale at any price. It seems that I have some how rubbed you the wrong way, for that I appologize.
Click to expand...

Don't take the "conspiracy theory" as an indicator of the character of this forum. I personally thought it was nuts to suggest such a thing.
 
No rick r you didn't rub me the wrong way, my comments were a little tongue-in-cheek.

I don't really sit here on the other side of the world getting all concerned about single carbs on dual manifolds. (But it's nice to know others are concerned enough to comment re: my comment). LOL.

The question still remains, why use a single carb on a dual manifold when surely the original manifold will do?
 
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