I brought the engine and transmission assembly up from the bottom. I already had the k-frame and front suspension out anyway and the car was on a hoist. It was very easy to do, with everything mounted to the k-frame first and then the body lowered over the assembly.
I have a 72 Challenger with a 340/automatic. It's the second Challenger I have had. I started out just to get to repainted about 21 years ago, then we decided to do everything and now it's finally going back together.