The Ford Barn

nickthebandit · 07-26-2025, 05:47 AM

I have 2 Stromberg 81 carburetor bodies that the accelerator pump hole is the same size as those in Stromberg 48, and 97 carburetors. These are not something that someone hogged out. They are as cast, factory sized. I know of someone else who also has 2 carburetor bodies like that. Does anyone have knowledge as to why these bodies are like that. Any info will be appreciated. Thanks, nick.

deuce lover · 07-26-2025, 06:13 AM

Is the Venturi size and also the base butterfly size as an 81? Uncle Max might know.Contact him.He is a member here.

hueyhoolihan · 07-26-2025, 06:30 AM

just a guess of course, but...

if you're referring to the diameter of hole in which the the plunger sits...it's possible that the length of its travel (it is driven by a lever, after all) compensates.

as it would be much more economical to change the pivot point of the lever, or make it longer or shorter or even change the size of the nozzle (spritzer) openings, than to have three different castings, i would think.

deuce lover · 07-26-2025, 01:13 PM

Those 3 carbs 48,81 &97 have different CFM's and each has its own venturi size SO 3 different castings.

petehoovie · 07-26-2025, 01:25 PM

Terry,OH · 07-26-2025, 06:19 PM

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The top cast body marked 67 is from a small logo 97. You are correct the 81 accelerator pump is different from the 97, 48 & 40. I do NOT know if the the pump diameter is smaller. Max is the man!

scicala · 07-26-2025, 08:10 PM

Yes, The 81 accelerator pump piston is a smaller diameter than the other Stromberg models.

Sal

L-head · 07-28-2025, 07:23 AM

Could the 81 center bodies be "modified" to circumvent the rules of a "racing" series? Carbs had to be 81's but modified to perform like 48's or 97's?

Bored&Stroked · 07-28-2025, 09:24 AM

It is pretty obvious which carb bodies are 81's - vs 48's or 97's, so I don't see an easy way to modify them to "cheat" the rules. All somebody would need to do is take a look down the venturis.

With that said, those who want to cheat find all sorts of innovative ways to do so!

nickthebandit · 07-28-2025, 12:02 PM

I have contacted Max Musgrove about this question. Max seems to think that some very creative person may have altered the carburetor body. I don't think so. I now have 3 Stromberg 81 main bodies that are as cast from the factory, and they have the accelerator pump hole the same size as those for model 40, 48, and 97 carburetors. I miss Bruce Lancaster, he was a fountain of knowledge.

deuce lover · 07-28-2025, 12:43 PM

Measure the venturi's and the base butterfly openings to compare to an "normal" 81.

nickthebandit · 07-28-2025, 01:18 PM

I did this, and they are the same as a regular Stromberg 81.

Terry,OH · 07-29-2025, 07:04 AM

You may be able to sleeve the bores back to the original size or try using a 97 pump.

Bored&Stroked · 07-29-2025, 11:00 AM

Why not just use the 97 pumps?

nickthebandit · 07-30-2025, 03:02 PM

As far as I am concerned, I will use 97 pumps. I would still like to know why these carburetor bodies were made this way.

07-26-2025, 05:47 AM	#1
nickthebandit Senior Member Join Date: May 2010 Location: Shippensburg, pa. Posts: 513	Stromberg 81 question I have 2 Stromberg 81 carburetor bodies that the accelerator pump hole is the same size as those in Stromberg 48, and 97 carburetors. These are not something that someone hogged out. They are as cast, factory sized. I know of someone else who also has 2 carburetor bodies like that. Does anyone have knowledge as to why these bodies are like that. Any info will be appreciated. Thanks, nick.

07-26-2025, 06:13 AM	#2
deuce lover Senior Member Join Date: May 2010 Location: Southern France Posts: 5,837	Re: Stromberg 81 question Is the Venturi size and also the base butterfly size as an 81? Uncle Max might know.Contact him.He is a member here.

07-26-2025, 06:30 AM	#3
hueyhoolihan Senior Member Join Date: Dec 2024 Location: central coast california Posts: 260	Re: Stromberg 81 question just a guess of course, but... if you're referring to the diameter of hole in which the the plunger sits...it's possible that the length of its travel (it is driven by a lever, after all) compensates. as it would be much more economical to change the pivot point of the lever, or make it longer or shorter or even change the size of the nozzle (spritzer) openings, than to have three different castings, i would think.

07-26-2025, 01:13 PM	#4
deuce lover Senior Member Join Date: May 2010 Location: Southern France Posts: 5,837	Re: Stromberg 81 question Those 3 carbs 48,81 &97 have different CFM's and each has its own venturi size SO 3 different castings.

07-26-2025, 01:25 PM	#5
petehoovie Senior Member Join Date: May 2015 Posts: 10,155	Re: Stromberg 81 question

07-26-2025, 06:19 PM	#6
Terry,OH Senior Member Join Date: May 2010 Posts: 5,187	Re: Stromberg 81 question Sponsored Links (Register now to hide all advertisements) The top cast body marked 67 is from a small logo 97. You are correct the 81 accelerator pump is different from the 97, 48 & 40. I do NOT know if the the pump diameter is smaller. Max is the man!

07-26-2025, 08:10 PM	#7
scicala Senior Member Join Date: Jun 2010 Location: Detroit suburb, MI Posts: 3,794	Re: Stromberg 81 question Yes, The 81 accelerator pump piston is a smaller diameter than the other Stromberg models. Sal

07-28-2025, 07:23 AM	#8
L-head Senior Member Join Date: May 2010 Posts: 183	Re: Stromberg 81 question Could the 81 center bodies be "modified" to circumvent the rules of a "racing" series? Carbs had to be 81's but modified to perform like 48's or 97's?

07-28-2025, 09:24 AM	#9
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,723	Re: Stromberg 81 question It is pretty obvious which carb bodies are 81's - vs 48's or 97's, so I don't see an easy way to modify them to "cheat" the rules. All somebody would need to do is take a look down the venturis. With that said, those who want to cheat find all sorts of innovative ways to do so!

07-28-2025, 12:02 PM	#10
nickthebandit Senior Member Join Date: May 2010 Location: Shippensburg, pa. Posts: 513	Re: Stromberg 81 question I have contacted Max Musgrove about this question. Max seems to think that some very creative person may have altered the carburetor body. I don't think so. I now have 3 Stromberg 81 main bodies that are as cast from the factory, and they have the accelerator pump hole the same size as those for model 40, 48, and 97 carburetors. I miss Bruce Lancaster, he was a fountain of knowledge.

07-28-2025, 12:43 PM	#11
deuce lover Senior Member Join Date: May 2010 Location: Southern France Posts: 5,837	Re: Stromberg 81 question Measure the venturi's and the base butterfly openings to compare to an "normal" 81.

07-28-2025, 01:18 PM	#12
nickthebandit Senior Member Join Date: May 2010 Location: Shippensburg, pa. Posts: 513	Re: Stromberg 81 question I did this, and they are the same as a regular Stromberg 81.

07-29-2025, 07:04 AM	#13
Terry,OH Senior Member Join Date: May 2010 Posts: 5,187	Re: Stromberg 81 question You may be able to sleeve the bores back to the original size or try using a 97 pump.

07-29-2025, 11:00 AM	#14
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,723	Re: Stromberg 81 question Why not just use the 97 pumps?

07-30-2025, 03:02 PM	#15
nickthebandit Senior Member Join Date: May 2010 Location: Shippensburg, pa. Posts: 513	Re: Stromberg 81 question As far as I am concerned, I will use 97 pumps. I would still like to know why these carburetor bodies were made this way.