I got my hands on a pre magnum 360 518 without lockup - it came froma 92 3500 van - I would recomend you get the 2 pin ( no lockup ) OR 3 pin ( lockup ) but dont get the 5 pin conputer controled tranny... mine is a 2 wire connection and done.

magnum motors are computer controlled and will have more trouble connecting it to a standard non computer controlled car.

i vote for the 518 ( KEEP IT MOPAR) and contact SMR trans.. google search them - pat is a good guy with alot of the info your looking for!