Correct carb

KarlJS

KarlJS

Senior Member
I have a 39’ 1/2 ton truck with a 24 stud 8BA engine (unknown year). It has a Stromberg 97 carb on it but I can’t get much over 30 miles per hour. Wondering if I really need the 94 carb instead? Thanks for the help
 
The 97 does not have the carburetor venturi vacuum port to properly operate the vacuum advance mechanism on the distributor your 8BA engine. If the vacuum to the distributor is hooked to manifold vacuum fitting under the carb, that could be your problem.



Find a 94 with the correct vacuum connection.
 
Yes the vacuum line is attached to the manifold, where should it be attached?
 

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On 19Fprdy's second picture, you can see the correct connection location for vacuum to your (presumably stock) load-a-matic distributor. It is about 2" above the right idle mixture adjust screw. There are a dozen versions of the Holly 94; find one that has that vacuum port, get it professionally rebuilt by one of the experts on this site, and you should run much better.
 
The Paradise Valley Model A swap meet is Saturday September 30th at the Little League HQ in Devore. You should be able to find a 94 there.
 
Hold it. I think some clarity is needed here. "19Fordy"'s post is incorrect. The port in the first picture with the tape wrapped around it is the vacuum supply for the windshield wipers; it is NOT the port for the Load-a-Matic. That port is in the back of the middle section on the carburetor. That port is clearly shown in the second picture, although it has a slotted-head brass plug in it.

The only reason that the "(e)ngine ran great in a 40 Ford" is because the engine in the fourth picture does NOT have a Load-a-Matic distributor. It looks like a later model Mallory to me (the red cap). I believe that some of those were available with vacuum over centrifugal advance. If so, it would share the vacuum source with the wipers.
 
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What diameter tubing should be used for the vacuum line from (vacuum advance mechanism ) distributor to manifold?
 
KarlJS said:
What diameter tubing should be used for the vacuum line from (vacuum advance mechanism ) distributor to manifold?
Click to expand...

Here is a thread where this line is discussed. https://www.fordbarn.com/forum/showthread.php?t=208212.

As you can see, the line requires special fittings known as "Ford Nuts" that are getting more difficult to source, You would be better off getting a new line and fittings (if available) or perhaps a used one (the steel tubing is also a real bear to bend exactly right). I may have an extra at my shop. I'll check tomorrow.
 
I stand corrected and apologize for the misleading information. Tubman is 100% correct regarding what I said in my post.
The distributor I was using at the time was a Mallory with mechanical advance.

Thank you Tubman for your sharp eye.
Jim
 
Didn't 'fan on crank' engines use a 91/99 Carb with the front bowl external vent? Newc
 
Newc, you are correct about original carburetors used on 39-41 Ford V8s. However the engine in question is a 49-53 8BA style with factory distributor and needs to have a matching carburetor.
 
My main question is what carburetor I should have on this engine. 24 stud 8BA, currently has Stromberg 97 with vacuum attached under carb (see previously picture) can’t get much over 30 miles per hour. Been told I need Holley 94 with vacuum connection located behind (firewall side) of carb. Then is it possible to get vacuum line?
 
I do not find an online source for that steel vacuum line, probably because there are hundreds laying around engine shops. Maybe someone on this forum could send you one.
 
The carburetor you need will have the vacuum port on the back side and a matching base without spark control valve, but with a passage that connects to the center port (I have seen mix & match assembled carburetors with earlier bases swapped on, that won't work for you).

Make your own line. You can get the Ford Nuts at Napa and other places. I ordered 4 early this year, picked up 3 (they didn't have the 4th in stock even though the computer said they did), and 2 matched so that is what I used. Third Gen Auto (regular contributor here on the Ford Barn) sells the nuts with two different wrench sizes:
https://thirdgenauto.com/product/new-1928-53-ford-vacuum-line-fitting-pair-uses-3-8-wrench/
and
https://thirdgenauto.com/product/new-1928-53-ford-vacuum-line-fitting-pair-uses-7-16-wrench/

Get a straight piece of tubing and bend it to fit your motor. Follow the picture of a factory 8BA and you can't go too wrong. Steel tubing is fine, no need for stainless, and since it uses the Ford Nut no need for flairing.
 
May be worth a try if Carpenter carb is too expensive. Be sure to check the float level before you run it. Also, fill the bowl and let it sit on your bench for a while to be sure it does not leak down past the power valve.
 
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