I recently acquired a 1940 Ford deluxe that hasn't been started for over 25 years. I'm going through the car now, new fuel tank, cleaning lines etc. it had dual carbs on it and when I removed them to rebuild I noticed the rear carb had a block off plate on the manifold and the fuel line had been blocked as well. My question is can this flat head run with the two carbs fully functional? I don't know what the engine has in it, it does have Edelbrock heads and offenhaiser intake. Thanks for the help.
I once had a tri power 97,s on a flathead and the front and back 97 closed off as you mentioned. I’ve heard on some duel carb setups the manifolds could starve the engine . Run both you can always jet it down
Yep, fixed linkage is probably best, check power valve size, - generally 3.5 to 4.5 each and balance them. Probably run better than the current set up if you have a little knowledge and time spent on them. More info here…… https://www.jalopyjournal.com/forum/threads/links-to-holley-94-technical-info.286574/
A lot of guys run blocked off carbs because of frustrated patience. The best are set up with straight linkage and proper jetting.
Wait a minute guys, it is important to know what kind of manifold he has. There are three basic types of flathead intake manifolds. The first is the "Super", where the two carbs a placed directly over the intake ports. he second is the "Regular", where the carbs are also spaced equally apart, but are a bit closer together. These types must be run with a straight linkage. The third (which this guy appears to have), what I call a "Biased" type. With this type, the front carb is located almost where the carburetor on a stock manifold is located, right in the middle. I believe this type will actually run better with a progressive linkage, with the front carb being the primary. This way, the car will run on the front carb 95% of the time, with the primary supplying fuel with distribution nearly the same as a stock manifold. At full throttle, the rear carb will kick in, supplying an extra shot of fuel mixture, distribution be damned. I contend the one of these would run worse with straight linkage, as the rear carburetor would feed fuel mainly to the rear cylinders, creating an over-rich system. I suppose that this could probably be somewhat compensated for with different jets, but I don't think it would ever be ideal. As for running with the rear carb blocked off, it's probably OK, as I'm sure this would run much like a stock setup. If some of you want to disagree, I have attached a clearer picture of one of these manifolds. Take a close look at the location of the carburetors, relative to the intake ports.
Yes you can. I believe these manifolds were made more for "Johnny Racer" rather than those seeking maximum performance.
I'm running the 8BA version of that Ofenhauser intake with two 94's and progressive linkage and it runs better than it did with solid linkage. The front carb is almost in the stock position and the fuel distribution seems to be okay. Flathead is an 8BA with a 3/4 cam from H&H and early heads since the center outlets work out better for the top hoses. I did have a problem with the carbs leaking until I put a pressure regulator on it, I was told the pressure is too high on some of the new fuel pumps.
Not to pick nits, but that manifold looks more like a "Regular" to me. Look at the position of the rear carb vs. the picture I posted. Your back carb is well forward of the back four ports, while on a "Biased", the back carb sits right on top of the back intake ports. Also. compare the location of your front carb in relation to the center water outlets in the picture supplied by the O/P and the one I posted. While I am mildly surprised that it runs better with a progressive linkage, I believe you when you say it does. This just lends credence to my contention that the "Biased" type would be even better suited for a progressive linkage (or a blocked off rear carb). Please note that the picture I posted is of an Offenhauser manifold.
I run one of those offenhauser manifolds that you call "biased" on my flathead and I have run it with straight linkage and also with a progressive linkage. It worked fine both ways. The dyno results I saw showed a slightly better performance edge to the "super manifold"
in my defence, - from the thumbnail pic and looking at the length of the ‘modern’ generator, I thought it was a ‘regular’ type. I still can’t tell either way which it is. Better photos always help……..
My intake manifold is an Ofenhauser and I see what you are saying about the carb placement, mine are farther forward than on the manifold you pictured. The cfm on a Holley 94 is listed as155 to 185 which is over carbed for a 239 flathead, with the progressive linkage it runs on the front carb up to about 60% throttle and both carbs are fully open at wide open throttle. When I ran solid linkage I adjusted the carbs with a vacuum gauge to balance the flow and it always ran rich.
Sorry I hadn't responded sooner but thank you all for the information, looking to purchase new strombergs vs rebuild these just to save time. the rear one is locked up pretty bad. any preference between the stock CFM and Big 97?
Mine's a 59-A, early Navarro 'Super', 2 small 97s, Winfield SU1A cam. Just a nice street combo. I'll use straight linkage, and jet it.
The word is to use (I’ve no experience) Clive from Englands 97s. I recall he has distribution in the US. He’s also been good on tech support. Just p***ing on the info I’ve gleaned here on the HAMB.
The Jalopy Journal
