Considering the engine weighs 900lbs, I don't think it's really a good candidate for a diesel swap. Some people have done it though. Not that much to it since the engine doesn't need much to run on it's own. Just have to mate a transmission like a NV4500,TH400 or 4L80E. I would consider a D60 front as well. I believe your best bet is to get one from a mid to late 80's Lay's P30 truck. There were the only tucks to use them, otherwise, you're going to be using one from some generator or pump.
I'd also really look at gearing. They produce a lot of torque BUT have a really narrow powerband. You can not rev them high. 5.16's might be too low unless you don't plan on driving on the street.