Hi guys! I have a 302 clevo with 4bbrl intake manifold and there is a "3" cast in the corner of bottom edge. They are cast heads and I dont want to pull the heads off to check for certain. is there another way to check if they are 2v or 4v? I do live in Australia and I read that Australian and Boss heads were not stamped in the top corner? Its not a boss, 2 bolt mains, standard 2v/4v damper. I was always told a 2 or 4 is stamped in the corner, this has a "3". HELP????