2.6lt Engine needed

I have a 1988 D-50 that I am trying to find an engine for it. I have been trying to get this on the road for over two years off and on. I have replaced the pistons and rings, turned the crank, new bearings, and a few other things. I just had the truck running a month ago, and it started to run bad and then quit. I have water in the oil, so I remover the head and every thing looked fine. I remembered that the bots were the same ones from the other head gasket job. I need to find one that is in running condition, or a cheap re manufactured short, or long block. If anyone has any ideas, let me know. Thanks kstokes606