Technical Holley 94 set up

I’m putting 2 Holley 94’s on my 59a with progressive linkage to start I’ve got 4.5 power valves in both carbs the secondary has no 50 jets the primary has no 59 jets with adjustable needles , what are you guys having good success running on your engines with duals , my engine has a 60 overbore , 3/4 race cam Navarro heads and the intake is a offenhauser with a t5 gm transmission 5 speed

 

First off, what kind of manifold do you have? If you have the wrong kind of manifold, trying to run progressive linkage with dual carbs will not work very well as the fuel distribution will be very uneven..

 

I just got through building up a similar setup for the 276” flathead I’m putting together for a buddy. We’re using an Edelbrock slingshot, 2 94s with #50 jets and 3.5 power valves in each to start with. We are running straight linkage instead of progressive though.
Curious to hear what the hamb flathead gurus have to say.

 

There are at least 4 very different types of dual manifolds for flathead Fords.

The first is the "Super" dual with one carburetor positioned directly over each set of 4 Intake ports :

Then there is the "Regular", with two evenly spaced carburetors, but closer together :



Next is what I call the "Biased" type, with the front carburetor positioned about where the carburetor is on a stock manifold, with the rear carb back towards the fuel pump :



Then there is what I call the "Oddballs", the best example of which is the "Edelbrock Slingshot" :


Of these, the first two are not good candidates for use with a progressive linkage; if you look at the pictures, I think you can see how the fuel distribution would be very uneven. A "Biased" manifold can be used with progressive linkage with the front carburetor as the primary. Positioned as it is about where the carburetor on a stock manifold is, you will get pretty even fuel distribution while running on one carburetor, with the distribution only going askew when the secondary (back) carburetor kicks in. The "Slingshot" is probably the best one to use with progressive linkage, as the air/fuel passages are quite close together, kinda like a 4 BBL.

That being said, a straight linkage is probably better in all cases.

 

I agree with those above. Stay away from progressives when running two carbs.
Also the use of a unisys is recommended.
Using a synchronizer will enable good fuel atomization.
https://www.jalopyjournal.com/forum/threads/flathead-idle-issues-help.863639/

 

I am running an offenhauser 1090 style dual

 

A Offenhauser 1090 is a "Biased" type. They have the extra advantage of being able to run the generator (alternator) in the stock position without extra brackets. I have never run one, because I consider them to be a compromise at best, with more thought given to generator mounting than to fuel distribution. That being said, they are a candidate for using progressive linkage with the front carburetor being the primary. Since it is almost in the stock location, the fuel distribution should be reasonable when running on the primary only. with the rear cylinders getting the lions share of the fuel when the secondary kicks in. If you end up running a progressive, it would be interesting to see how it works out, so keep in touch.

I now run Rochester 2G's on a car with a hood; probably more CFM than duals and a lot less trouble. (I used to run Holley 390's, but the Rochester carbs and Merc manifolds are currently a lot cheaper than a comparable 4 BBL setup and perform just as well) . On a car without a hood, I am partial to a "Super" dual with .050 jets and plugged power valves (and straight linkage, of course). This setup was suggested by a gentleman known as "Charlie ny" on "The Ford Barn". He knows everything there is to know about 94's and has rebuilt a gazillion of them, so he is the "go to guy" for them. I don't know that plugged power valves would be the best solution for the setup you are considering, seeing that it would operate completely differently than a "Super" with a straight linkage. Your best bet would be to go to "The Ford Barn" and get to know it's ins and outs, and then pose the question to Charlie himself, although you might not like the answer.

 

I was running straight linkage on 2 super7 generic strombergs from speedway that ran fine but after talking with Charlie Price owner of vintage speed in Florida I decided to go with the original 94’s with the progressive linkage for a more of a 4 barrel feel when you kick it down , he has many videos out about carburetors and building them , check him out on the inter web , just gotta find the correct power valve and jet combo for best response and power

 

I run a similar setup with two '94s on an Offenhauser street manifold ( front carb is close to the center and the other is offset to the rear). I have used straight linkage as well as progressive. The problem with progressive is that the secondary carburetor throttle plates will stick in the bore if you shut them completely. If you don't shut them completely they will bleed air and mess up your idle and low speed operation. You can buy new throttle plates with special bevelled edges to help with this. Instead I went back to the straight linkage. Performance is great that way. I definitely use power valves in both carbs. I have tried running with one or both plugged but it works best with both power valves.
Now as to the question of unequal fuel distribution, take a look at a 6 or 8 cylinder inline engine with a single carburetor and you will see very uneven manifold spacing but it doesn't seem to affect performance. Actually it does have a small effect. I read an article comparing performance of flathead manifolds and the super dual outperformed the street manifold by a very small margin. I doubt that you would even notice it at the seat of your pants. So try the progressive linkage with your setup without worries about fuel distribution and have some fun with it.

 

I would never use adjustable jets. Also I am not a fan of eliminating the power valves.

 

^ goodbye to all that

 

On most if not all of the 2x2 setups, I have built them with straight linkage, some could be changed to a progressive set up, however as above, the intake manifolds are not setup to run progressive. Look at the runner length as an example of these intakes having long runners. The shotgun would be a better use for the progressive linkage.