The shorter one looks as if it doesn't have the split skirt that the taller one has. Has somebody machined it down? The last time I saw something like that was a mate many years ago who made a home made big bore kit for his 550, using 750 pistons, and took some off the crown and the skirt by hand with a belt linisher. None of them matched heightwise, but he ran it hard for just over 3 years, until he holed 2 of the pistons. When he took it apart afterwards, the ones that holed had a crown thickness of just over 2mm, amazing it Lasted that long!
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