What year is the van? If you are lucky, and the 727 in the van is a non lock up transmission, and you have a 727 instead of a 904 in your Dart, all you need to do is move the torque converter from the Van 727 to the 727 in your Dart and that part is solved. Use your distributer from the 318 and all of your wiring in the Dart should work right back. Pay attention to the oil and temp sending units to see if they are the same between the 2 motors, and if they aren't and your gauges are working fine in the Dart, use the 318 sending units. You will need to get a 360 car oil pan and put it on before you drop the 360 in the Dart. Your existing motor mounts will work back, but you will need to add spacers such as flat washers to the drivers side mount, between the ears on the block and the motor mount bracket. Flat washers work just fine.