The average Pantera on modern tires is easily capable of cornering hard enough at an autocross to drive all the oil away from the oil pump pickup momentarily. The oil pressure gauge sender is at the far end of the oil gallery so a momentary drop may not register. But if you do this often enough, the bearings will suffer, which is why most engine builders nowadays will not sell you a 351C for a Pantera unless it has a fully baffled 10-qt oil pan. That said, I doubt if the engine seized; more likely its some sort of electrical problem with the key, ignition or starter. One difficulty I always had with the gated shifter was putting the shift-stick in one gear while due to to shifter flexibility, the ZF would slide into another gear and took a solid smack to pop it back into neutral. But once you sort it all out, if you intend to continue autocrossing (which is fun!) I suggest you check into a good aftermarket oil pan such as the Aviaid sold by most of the vendors
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