Thanks Phil, the gentleman I bought them from said he bought them years ago as nos. and paid more than what he asked for them but he very well could have been duped also who knows. The combustion chambers are gray but seem to be a much lighter gray than John's picture, of course that could be just the pic. From all the input I've heard so far there isn't any real defining mark or stamp to let you know for sure which heads are which. The bolt holes being drilled a little off center, dark combustion chambers, and roughly finished fins around the water pump housing can give doubts but I was hoping to find something that would let people tell the difference right away without doubt. It really doesn't matter to me which I have, I'm very happy to have them either way, just thought this would be educational for us all. Thanks to everyone who has replied so far and hope more will add their thoughts.