99 cobra to an automatic .what i need?

Trasmission out of any 4.6L Mustang. Ford 150 or other 4R70W's may work.

Flywheel from 99-01 Mustang 4.6L automatic style

Driveshaft and yoke from 96-02 Mustang 4.6L automatic style

ECM from 4.6L Mustang automatic type. (numbers may not matter since you should get it tuned anyways.

Shifter assy. with bezel and with cables.

Brake pedal assy.

The steering colulmn you can leave alone. Just take out the switch that you must push in when removing the key on a stick car. Only 1 bolt holds that to the column's housing.

These are the major parts, but a good shop (Mustang Speed Shop) will need to tune the car depending on what trans and computer you used. As far as wiring for the trans, you may have to buy that auto trans harness from the dealer. Or the best thing find a salvage yard that has a donor car.