John! Just seen the thread...
IF you get the computer with the engine and trans, then it makes no difference on the trans. RH is the Hyd., AKA, no computer needed, RE AKA electric/electronic shifted trans, computer needed.
All Magnum heads should be considered cracked and able to be run as is no issue since the cracks, if not out of control and freakishly huge, are not an issue.
Any engine/trans gear would do IMO.
So for me, the one with the lowest miles wins the spot. Your only need is a rear wheel drive truck/SUV.