Maybe someone can confirm it, but I think I remember the 6.2l GM diesel block is a 350 cu. in. block, just different other parts. The 6.5l GM diesel is also the same block, different stroke and a turbo. Both are mechanical motors, and the weight isn't too much different. The idea of a tractor engine mod is pretty cool, but way past my patience. I think you will find one of those two will be a better fit for you. Put a solinoid on the inner fender for with a switch on the dash for glow plugs, fuel filter swap, and maybe a little research for your fuel tank, and I think it could be done. We bought a '84 gmc with a 6.2l diesel for $2500 last winter. You can find them pretty often for prices like that. The glow plugs are a pain to change, being located under the exhaust manifolds. We used to swap the 6.2l's for the turbo 6.5l's in Humvee's when I was in the Army. Overall, motor wise, the 350 should be a bolt in for the 6.2l or the 6.5l. The fuel filter and housing I picked up at Napa, I don't remember the price. The solinoid is also a very common Napa item.