1968 DODGE 300 DUMP BED 1 1/2 TON FLAT BED

I bought this truck with intentions of using it for cleaning up my rentals. Well it has been sitting here for 2 years now its time to go. The engine runs just not well. We did a compression test on the engine and there is about 4 cylinders with very low compression then we squirted oil in those cylinders and the compression did not change so the diagnoses is the valves are burnt in those cylinders. I think a comings diesel from a newer Dodge ruck would be a nice swap or fix the 318 that is in it now. I drove the truck home and it drives just fine. Thanks for looking