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long versus short manifold question

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I'm trying to "mix and match" a couple of engines to get one a little better running for my AC B10. One has the short manifold and the other the long. Is there any advantage to using one length manifold over the other? Any help/advice will be appreciated. Thanks.

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In performance car tuning I have heard of using spacers to increase the throat depth from the fuel point to the intake valves(thus supposedly increasing atomization quality) but I don't think on our level of performance that it matters very much. Perhaps in a pulling environment with a red-lining engine there could be a difference but again it would be unlikely to be noticed here.

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The one thing nobody has mentioned is the height of the fuel tank. With a short manifold some tractors will run out of fuel while there is still fuel in the tank. The longer manifold puts the carb lower than the tank on most tractors.

The longer manifold should produce more torque, but it also has a larger volume which does not allow for a quick progression of a pulse from the engine to the carb. I have tried both and if I can use it I usually like the short manifold. Seems to work better on my tractors.

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