I checked with a friend from the past that owned and raced a vintage 911 built by Wolfgan Mikie (sp) that used a set of these (cheater pistons). During his search to replace them he identified them and subsequently replaced them with the proper size Mahles.
They are in fact EMPI pistons. I would like to see the cylinders.
EMPI actually made pistons and cylinders, biral in fact around the same time they made the big bore biral barrels for 914 / VW type IV engines.
They do look allot like early two liter pistons.
