A couple of summers ago I bought a New Holland 655E backhoe as a fixer upper project to clean up fencelines and to do tile repair.  It had a lot of hydraulic leaks, most of which, I have repaired.  I discovered that it overheated when it ran for very long, so I started chasing that problem.  I have had the radiator thru the local shop. I'm not positive, but I think they re cored it. At the least it was hot tanked and leak checked and flow checked. I replaced the head gasket, had the head resurfaced, and had the valves done.   It was still overheating so I had the water pump rebuilt at AP air in Humbolt, IA.  It still overheats within 10 minutes of driving it at wide open throttle going down the road.  This has been nearly a two year project that I've just been playing with when I have time.  It's not something I use every day or even every week.  If I just idle around it works okay, but traveling to clean up fencelines or to do tile repairs is problematic.  The block looked good when I had the head off,  no obvious cracks or problem areas.  There doesn't appear to be antifreeze in the oil.  Any other suggestions as to where to look?  It's not a critical machine that I depend on, but I would like to make it reliable.