Okay i got my used 6.0L in today, tore it down and it appears that the head gasket had been blown but didn't look like too much damage was done. When i hooked up compressed air to the cylinders it just blows out into the crankcase?? The air drives the piston to the bottom of it's stroke but then it just leaks out of the cylinder? The oil pan is off but sholdn't the cylinder still hold compression. Is this normal with the oil pan off or did I just buy a new boat anchor

 

Anybody???

 

The cylinders aren't 100% sealed so air will pass over the rings when you hook up a compressor to it.
Do a compression test to find out more about if its good or not.

 

A little air will pass through, but not a lot. compare to the other cylinders, if one stands out from the others, its not a good sign. If the oil pan is off already, take a look and even consider poking around a bit.