Assuming you don’t want to remove the engine, it can be done in the car. It involved loosing the motor mounts, lifting the engine high enough to be able to pull the pan out from the engine and cross member space. As I remember doing the same on a 72 Ranchero, I had to remove the trans crossmember to let the tail of the trans down. If you search 7173mustangs.com, using Google to do that, I suspect you‘ll find someone who has posted pics of the operation.