I would e-mail Ted on this one. Obviously, your car is wired a little differently or someplace along the line, the high & low beam wires to or from the fuse were switched. Very early Panteras were rewired at Ford dealers for a variety of weirdnesses by DeTomaso; possibly 1448 was one. The simple fix is to remove a high and a low beam wire from one bulb socket and swap them but I'd try to find out how it happened too. Especially if it works right with your stock bulbs.
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