Piston Identification please

So I took my heads off as a few of the bolt holes for the intake were stripped. The machine shop has got them all fixed up, magnafluxed, and changed the old school teflon valve seals for some new ones. They said the old X heads are in good shape ..... few. I had a good look at the cylinder bores and I can still see most of the cross hatching. The pistons are not stock and I'm looking for some help to identify them. The numbers on the top are L2316 030. I assume the 030 is for .30 over bore and have no idea what the rest means. I'm hoping one of you can identify them.

Thanks

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Author: admin