yeah they make whats called a copy lathe which is a whole different machine.
i don't think you can modify your lathe into a copy lathe. not sure but i really don't think you can.
what the copy lathe does is, you put in a pre-made crankbait, and then set the copy wheel on it, and then next to that you put in your block of wood, and the copy wheel is connected to a blade and as the wood turns, the copy wheel follows the contours of the pre-made bait, and since its connected to the blade, the blade follows the same contours and cuts them into the piece of wood.
them copy lathes sure are expensive