I have thought about this swap too,I have a '67 A100.You can use the stock A100 transmission since it will bolt to the 5.7 Hemi.As far as motor mounts,I wonder if any of the available A or B/E Hemi swap mounts will work. The 5.7 is wider than an LA motor,but is it the valve cover or exhaust manifold that is the widest point? One plus is the 5.7 is lighter than an LA motor,more power in stock form is another.
RT