The diesel swap is not as easy as it would seem. Requires a different fuel setup. On a Dodge pickup, you just get the gas tank and fuel lines from a diesel truck. The Cummins fully dressed is also 3 times heavier than the hemi, so even aftermarket springs would sag. Aside from the added weight, the frame may not be able to handle the torque. I have seen frame rails split in half after a cummins conversion.