Those Buick pistons are also available in .060 oversize, that will make that "216" a full grown 235 with aluminum pistons. Silv-O-Lite part number 1718-60.

www.summitracing.com/parts/uem-1718-060

That's an 8 piston set, but the price isn't terrible, even with a couple of leftovers. Many years ago, J.C. Whitney sold a "high compression head gasket"- - - -a solid copper gasket .030" thick that was supposedly designed to make a tiny difference in the combustion chamber volume. I've been in contact with a machine shop that claims to be able to use a water jet CNC mill to duplicate stovebolt head gaskets from a thin sheet of copper. Using studs instead of head bolts, and a solid gasket will probably avoid the potential problems with using 70 year old OEM gaskets with the increased compression gained by increasing the displacement of the 216 engine. Some "quick and dirty" guesstimates suggest it might be possible to build a 235 cubic inch engine that looks like a 216 from the outside, with around 8:1 compression!
Jerry

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