.I'm new to Banger World, found an original Thomas dual carb Manifold, which my '30 roadster demands I install. Is the stock fuel system capable of running a pair of '97's efficiently, or will I need a fuel pump etc. I have longer term plans, overhead valve B motor,among other things, but want to keep running in the meantime!!
I don't have any personal experience but have read that you are better off with a pair of 81's. Try asking on fordbarn. I think you can get away without a fuel pump just don't run up any steep hills with partially full gas tank (unless you are in reverse). The nice thing is that the Model B will have a fuel pump. Attached is a picture I took a couple of years ago at LARS. Charlie Stephens
Without other improvements you are unlikely to get much benefit from dual carbs. Along with a high compression head, performance cam and better ignition you will be surprised at the performance a Model A engine is capable of. Search threads on dual carbs; you will find that you need to go smaller on power valves and larger on main jets to get 97's to work. You need larger jets, not smaller because the airflow through each carb is cut in half and they stumble badly off idle with stock or smaller than stock jets.
I am running dual 97s on my little banger. They were on there when I bought the car, so... It also has high compression head, some non stock cam. is bored out, insert bearings and electronic ignition. It is tempermental. Today it runs great but tomorrow it may not. I have gone through the carbs and reduced the power valves and upped the jets like mentioned. If you intend on driving your car a bunch look into the 81s. Yes they do cost just a bit more than 97s, but better suited to the banger. Wish I had that option, but my stuff is getting swapped for a 8BA v8. Cool find and I hope you get it going and driving well.
My Model A was running a couple of 81's; which was temperamental too. The electric fuel pump was putting out about 14 psi and was throttled down with a Holley pressure regulator. I'd get it running good and go for a drive and it would start flooding. After playing with it for a couple of years, I'm in the process of converting it over to a couple of Carter-Webers. I know not traditional, but hopefully I'll be able to enjoy it a little more. I can spend my extra time on one of my other projects.
I ran a pair of Stromberg 81s on a mostly stock A. I chose the Thomas at the time because so many of the other dual intakes had ports that were obviously too large for the reduced flow of the 81s. Still there was a flat spot on takeoff that was difficult for me to figure so I gave it some revs to avoid the problem. In those times several intake combinations were tried but if there had to be duals, the Thomas and Burns were all I tried. Single Chandler-Groves (Ford Holley) worked very well with fewer problems after the power valves were changed to reduce premature enrichment or the pulse problem inherent to the banger. Wide open throttle use probably would seem different but the street calls for a more sober evaluation. What give up cool for smooth operation? Your mileage... I still have the Thomas+81s as it makes a great wall art, complete with the $65 price tag where it failed to sell at a swap. Probably worth telling, I used gravity from the A tank, no pump. Good Luck: Fred A
I ran a single 94 on my Model A without a fuel pump for a while, worked with a full tank of gas. Was about 50 miles from home and started up a long hill and ran out of gas, had about 1/2 tank. Had to pull over and wait for the carb to refill and went a ways farther before it did it again. Added an electric fuel pump and regulator after that. I have a pair of 81's I've considered using but never got around to putting them on, think two 97's will be too much carb.
I run these as duals on a stock motor with a high compression head, Mallory Distributor, and tube header. http://www.jcwhitney.com/omix-oe-re...3064049.jcwx?filterid=c2034d18864y1946g1232j4 They work really good. I run them on a Miller Schofield dual updraft intake that is flipped over. My next banger will get 2 97's but that's an entirely different monster. It's getting a lot of other tricks too
I've run these 81's on a Zepher intake on a B motor in my '31 A for several years without problems...stock tank - no fuel pump.
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