What are your recommendations for engine size and transmission. I was thinking 350 with the TH350... Any thoughts from anyone who has done this conversion and what obsticles do I face?

depends on what was in the car b4... if it was a 6cyl... u need motor mounts. radiator. front springs. then if u buy a used engine.. belts hoses.. and that whole deal...
probably about 300-500 in parts if u change out a 6cyl to an 8cyl..