Multi Carbs on Flathead thread

My personal favorite; three Chandler Groves(94's)
 

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On my GTO it's got a primary(center) and than secondary's are the outer carbs. Can you run a 3x2 flathead like this or are they all matched in linkages? Reason I ask is I always get "must be a nightmare tuning 3 carbs" comments on my GTO all the time and the setup has performed flawlessly for the 25+ years I've had my car. I currently have a 4bbl on my flathead and thinking of more power and wow factor but keeping it reliable. My Flathead isn't stock, had my engine builder do what it needed to make more power. 4" crank, msd, valves, custom Pistons, port matched and smoothed, Potvin cam etc etc. it's not in the car yet as I'm still building it but figure there's many on this site with a world of knowledge and experience.
 
I'm running 3 Stromberg 97s with Navarro intake and heads. 3 3/8 bore x 4 1/8 stroke. Progressive linkage. Runs like gang busters!
 
The GTO runs on the center carbs, when you floor the pedal a vacuum chamber open the end carbs, there even open or closed, the end carbs have no idle system. Walt
 
Walt Dupont--Me. said:
The GTO runs on the center carbs, when you floor the pedal a vacuum chamber open the end carbs, there even open or closed, the end carbs have no idle system. Walt
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All years of GTO tri power ('64, '65 and '66) never used a vacuum diaphragm to open the end carburetors. It was mechanical progressive linkage. Foot on the floor and all three carbs were instantly wide open.

Sal
 
scicala said:
All years of GTO tri power ('64, '65 and '66) never used a vacuum diaphragm to open the end carburetors. It was mechanical progressive linkage. Foot on the floor and all three carbs were instantly wide open.

Sal
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Actually, they came factory with a vacuum diaphragm secondary's, it was a dealer installed option to have them with mechanical linkage...at least for 64.

What about 4 carbs for my Flathead, too much carbs? A couple mentioned they are running them, are they re jetted? Thanks guys
 
[QUOTE.What about 4 carbs for my Flathead, too much carbs? A couple mentioned they are running them, are they re jetted? Thanks guys[/QUOTE]

The number of carbs you run is directly proportional to how "kewl"
you want to look, how fast you want to go and how much money you want to spend.
Very seldom can you buy carbs off the shelf, bolt them on and have the mixture right for any modified engine.
Yes, they are re-jetted normally.
An air/fuel ratio meter and plug readings are the usual methods of jet size determination.
A dyno is a big help also.
 
If you're looking to make a rational - as opposed to emotional - decision, John Lawson's book is tops. HIGHLY recommended. FWIW
 
Thanks for mentioning my book. Sadly, the average citizen isn't doing much reading or studying to gain more knowledge these days. And, I am not referring strictly to the subject of Flatheads. We all want the answer or bottom line without understanding the mechanisms.

JWL
 
"Actually, they came factory with a vacuum diaphragm secondary's, it was a dealer installed option to have them with mechanical linkage...at least for 64."



I didn't realize that. Thanks for the update. I was just going by cars that I had seen. Always learning !

Sal
 
JWL said:
Thanks for mentioning my book. Sadly, the average citizen isn't doing much reading or studying to gain more knowledge these days. And, I am not referring strictly to the subject of Flatheads. We all want the answer or bottom line without understanding the mechanisms.

JWL
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John:

Any chance you'd do a follow up to the book? As I mentioned in this post, I pull your book out to read it again this week. Really well done and informative.

What I mean by follow up is test other combinations that were tried in the first book?

For example: Edelbrock Slingshot intake with 97's v. 94's. Some additional cam selections.

This is easy for me to ask since I'm not tearing down and building up motors, but I would love to see other combos put through your logical testing process.
 
Carburetor set ups have always had as many variances as they have had different manifolds and different carburetors. Most folks will agree however, that the more complicated it looks the more bragging rights there are. I've seen folks make a lot of parts to get an old set of Winfields working just to be the only guy around that has them. Others just go for tried and true with the least amount of expense. I lean more toward the latter myself.
 
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