With all the questions I've had recently about the aluminum heads I thought I would pass this along. For those of you that have never seen one in person. Look at the radiator hose going into the head. On the Sherman it ends right there, on the stock head it tapers and runs almost the full length of the head. Look at the outer edge of the casting. On the stock head there is a generous curve or rounded edge, the Sherman is more square and a smoother surface. The top of the Sherman head is perfectly flat and there are "NO MARKINGS" any where on it.
Hope this helps, have fun looking for them at tractor shows now ;-) I've only seen two in use.