Taildragger 1785,
Big engine, flaps, slats, and wing modifications are not necessary to get off short. Your C-120 was built stock when most airports had short runways.
Get the tail up and airplane level as soon as possible. Get the mains off and airplane level in low, six inches, ground effect as soon as possible. It will fly in low ground effect long, long before it will fly in high, ten feet, ground effect. Stay in low ground effect until at max speed or something out in the desert forces you up.
Little, light airplanes can get off plenty short. They just don't climb real well, out of ground effect. At high density altitude, we little airplane drivers need to forget going up until we find some up air to ride slowly. We need to go fast in down air. We can always go like hell down hill.
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