If it's got 4.4 cast on the crank... I guess it's a 268. To be honest, I forgot that he posted that in an earlier post.
It's still nice to know with certainty what the engine is exactly. You know as well as me that there's some very tight unit code breaks on specific parts on those engines, particularly around the water pump... that he ought to know even if it's not overly relevant to ordering pistons.