I've never done this swap but I saw one just this week. Looked good, the guy was running a TH350 trans. I do believe the radiator has to be moved forward but I would leave the radiator support right where it is as all the front sheet metal attaches to it. I would think the radiator could simply be moved out in front of the support and spaced forward as needed.
Tom Langdon has the motor mounts and all the tech advice you would need for the swap.
Good luck, and I'm sure others with actual experience will chime in soon.
