I am going to bolt on some upgrages to my new stock 29 fourbanger engine. I want to get it running for summer. I figure I can afford a high compression head, headers and intake. The PO gave me a nice new modern distributor. Everybody I talk to says that a single downdraft carb would be plenty for this engine. But I'm thinking that I want to do more extensive performance upgrades later as a next winter project. Like balancing the engine, cam, shaved flywheel, etc. I'm thinking that for $300 extra I should get a two carb set up now. Why go to the expense of buying one type of manifold now and another one later(and losing money selling the first)? Couldn't I jet small and run the two carbs with the stock engine and have the set up in place for when the engine could use that much juice?
There are a lot of engines out there running twin pits that don't need them. I suppose that if you plan on upgrading you are ahead of the fellas that just run two carbs.
yah you can. But why dont you just go ahead and get a cam now, send yours in get it reground, adjustible lifters. Your already have the head off and whats the radiator and oil pan. Thatll give you real good performance.
I've been reading about swapping cams in a model a. The manual I have said you have to tip the engine over to get the lifers out. Is there a way to do it with the engine in place? Why would you have to drop the pan? I'd like a source for performance grind cams if anyone has one. My only parts catalog, Sniders, just does stock cams, I think. I'd also like a source for adjustible lifers.
FWIW We're currently using a dual carb manifold on a banger engine with a 'B' cam and a 6.3:1 head. We have 2 94's with the power valves removed and we are using adjustable jets. Even with the jets tweaked way down the engine is over carbureted. The plan for this spring is to take off the current setup and install a single carb Scalded Dog manifold with an '81 carb. Based on what we're seeing this should make it much more driveable.
The answer to this question depends on the size of the carbs, the state of tube of the engine(CFM requirement), and the design of the intake manifold. To provide the same flow to the engine a divided/split manifold would need two carbs the same size as a single carb on a common manifold. For anything other than wide open throttle racing, too little carb is easier to live with than too much.
As far as basic rule of thumb, that's correct. With an essentially stock A banger like we're talking about the engine is limiited to how much it can flow by it's design. When all is said and done, an engine is just an air pump. Best of luck! Here's a shot of the engine early on before we finished the car last year.
My 2 cents Brain is to run a single 94 save your money the 81 is to small. What Dia. lifter are you running if you have the cheap small lifters you are not getting all you can out of that B cam. The bigger the lifter the longer your valve will be open.
I took the pan off to get the lifters out. then you hold them up with cloths pins. I took my cam to crower and had them grind it. For banger parts there is, macs, reds headers, sacramento vintage ford, and a bunch of others. You need to join the monthly banger meet. i asked for a b grind but the guy at crower laughed and said hed make me go 100mph. Well it didnt but it gets to 55 pretty quick. I run a 6.0 head a reds header and a single ansen intake, with an 81. it runs absoultly amazing. The base of my carb sweats, so i know i got good velocity in it. I still want dual carbs.
I don't know if the guys that regound my cam could do yours, but it might not hurt to call them and ask. Try Oregon Cam Grinding. They are in Washington state. It cost me $70 for the cam and $24 each way for shipping.
My understand a reground cam doesn't give you more HP just keeps the valves open longer, to take in more air/fuel and exhaust it..All your doing is putting more air and fuel in a displacement and compression engine that is not enough..Displacement and compression is what gives you HP and torque, then you can think about more air and fuel.. Bigger cam doesn't give you more HP, just keeps the valves open longer so the engine can really run rich.. My nickel Duane..
I don't understand. If a "bigger" cam doesn't give more power, why doesn't everyone just run a stock cam, bore and stroke for more displacement and kick the compression up a few notches? I have to think that Isky, Herbert, Erson, Crower and a bunch of other cam grinders might dissagree.
Hes definetly right, If you really think about it. the engine doesnt even **** the air in. the atmosphere pushes it in, the piston just creates a void. the atmosphereic preasure is the greater force in the equation. The atmosphere also ****s the air out of your compresor. I learned this backwards **** in intro to physics.
My recommendation would be a single 94 or 97. Having said that I run three 81's on my Winfield 6:1 B engine, and it runs great. A cam isn't necessary unless you have a bigger carb and more compression. I grind cams, and they definitely improve HP but there is a slight loss at low speeds with a huge gain higher up. Write me at jimb4e4@gmail and I'll send you an article that I did on building a mild performance engine, or see the article at www.hotforhotfours.com
p.s. Always start with stock jets in a carb, and tune from there. Carbs are dumb and only know there is air going thru them. They don't know what's under them.
Do what you think is right, if an engine isn't built for more air/fuel why add more??? Putting a bunch of carbs on a engine doesn't mean it will run faster!!!!!!!!!!!!!!Build the engine then supply the correct amount of carburetion... I'm not saying a cam won't help but it has to match the engine.. Duane..
i tried 2 97's on my warmed banger . always way rich . went to a single 97 , still rich but much more friendly . none of my bussiness , but i would try a single 94 if i were to do it again ................. steve
I'm running a B-F super head, Crower cam, headers, Petronix ignition, a pair of the new 97's, inserts and a V-8 clutch. This engine is balanced and the crank has had counterweights added. I think that it's putting out an honest 100 HP + and will wind out to 4500 RPM. However, I've yet to build a banger that didn't cost at least twice the price of a pair of SBC crate motors!
^Just read your article. Seems like good straight ahead stuff to me... Look forward to talking with you when I do my "mild" engine soon. Thanks.
Ha, ha! You got a good point there. But then again, for the money I'm going to put in this car in all I could probably buy a fairly new car with more horsepower, that steers and brakes better and that never needs a tune up. But then I'd have just a used car and nothing to do in the winter.
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