but mostly the relating to the crank, heads,
look here, there are no bad engines, just bad engineers http://www.enginebuildermag.com/Article/1458/the_optimizer_6500.aspxgood info
The Optimizer 6500 diesel engine now produces 205 hp and 440 ft.lbs. of torque....Sorry, the bad news is that you cannot buy a new block from GEP.
I don't think these are necessarily bad engines, for a light-duty diesel. But putting them in the HMMVW was a bad idea.