What carb to use?

[De Konjel]

I hope you can advise me. Reading a lot but not sure yet.
I have a '31 Speedster and want a carburetor upgrade.
The engine has some modifications.
Head is 7 to 1 and a 340 camshaft. still with standard valves, but they are being modified to 1.73" Intake valves and 1.53" Exhaust valves.
What's your idea for carburetor?
Currently a standard Tillitson.
Could go for a double Tillotson.
A single Stromerg 81 or double.
A single Stromberg 97 or double.
Or perhaps a single or double Holley 94?
And why?

[Flathead]

Get Jim Brierly's book if you do not have it already. It's full of performance info.

[jeepguy1948]

The Holley 94 is a pretty good carbuerator. Some say better than a Stromberg. I have a Stromberg 48 on my model B motor and a 94 on my V8. The bad reputation of the Holley 94 comes largely from the fact that they were used to (vacuum) control the distributor advance in a vacuum advance ONLY distributor. This was Ford’s Load-A-Matic system and I have a strong dislike for that set up. It works ok if EVERYThing is stock and in good condition. This is rarely the case. The 94 can be used with a conventional centrifical or centrifical + vacuum advance distributor.

[jeepguy1948]

“Ol’ Ron” on here has written an outstanding book as well called “Nostalgia”. He wrote it 20 years ago so some things have changed a bit but it’s still great (I have a copy).

[nkaminar]

My downdraft Weber works great on my engine. It has two throats with progressive linkage. So for lower power requirements, the one throat provides good economy and when extra power is needed, the second throat opens up. You can really feel the difference when the second throat opens up.

[jeepguy1948]

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The Weber is a great Carbuerator, some feel that it is too small for a 200CI motor.

[jeepguy1948]

I imagine it depends on how many modifications have been done to the motor and how much horsepower is trying to be produced. The 32/36 is rated 270 CFM. The at 3,000 RPM a 200 CI motor needs 175 CFM so I would say that a Weber clearly has enough capacity, good to know.

[jeepguy1948]

Per the formula in Ron Holleran’s (‘Ol Ron/Gramps) book “Nostalgia” CID X RPM/3456

[Jim Brierley]

Contact me at [email protected] and I'll send you an article that I did on some dyno work about carbs.

[1930artdeco]

I use a Marvel in my 1930 Townsedan, the engine has been upgraded with a 'high' comp head and Counter balanced crank and shaved flywheel. That heavy cars does 55-55 al day long.