Ford 555D Backhoe Engine?

Have a Ford 555D, the engine developed a tick which quickly became a loud knock before it died. No holes in the block but I believe I have a major failure on the inside, looking for a used motor everything I have researched leads me to believe I have a 256 engine. I have had some tell me there is a couple of ford tractors that have the same engine. So can anyone with knowledge of this hoe give me some direction. Looking for a good runner used engine, maybe some info on what other tractors...

Ford 555D Backhoe Engine?

Ford 555D Backhoe Engine?