Here's a tech spec. page from the Silvolite catalog. These look like a pretty good set of street pistons, not quite as fancy as Speed-Pro, but very serviceable for street and/or mild high-performance use.

http://kb-silvolite.com/spistons.php?action=details&S_id=240

I usually use Speed-Pro hypereutectic cast pistons in the claimer engines I build. They're such a hard alloy it takes a carbide cutter to machine them!
Jerry

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