We have a 51 International Pickup that we want to convert over to a Mopar drive line. It was suggested that maybe a sub-frame from a B Body mopar would be a logical choice as we do not want to ruin the original frame by adding a clip from Dodge 1500 Truck. Has anybody out there had any experience with this approach.
We have a 360 from a 2000 Dodge as a Power plant.

The Plymouth subframe would need to be grafted to the truck frame as well. You can leave the front suspension stock (solid axle?) and buy a universal engine crossmember from JC Whitney or most rod shops. These are usually set up for SBC, BBC, or SBF engines, but you can modify the engine pads to fit the Mopar easy enough -- just drill new holes for the mounts. You'll have to figure out which one is spaced about like the Mopar though. If you want independent front suspension you can buy a Mustang II kit for your truck, or if you want to go the junkyard route find an AMC Pacer. You'll have to weld motot mounts to the crossmember, but the entire front suspension comes out with the crossmember. I've seen this used on late 50s Chevy and Ford trucks. Just modify the original AMC mounts (cut down) and either weld to the IHC frame or weld plates to the IHC frame and bolt the front suspension on using the original AMC rubber mounts. The later will get you a better ride, welding to the frame will drop it an extra inch. A bonus is the Pacer front suspension comes with a power rack and pinion steering setup.

How crazy do you want to get with this truck? I just finshed a 67 IH I used a 78 Caprice front end and the driveline lowered it 8" it rides like the wagon did. i've got pictures if you need ideas