I finally got down the IPD big bore piston set with one slightly damaged by
impact with a 5/16" hex nut.
This is for a 6 bolt, 2130cc engine, 92mm/3.622" bore.
| = perpendicular to wrist pin, - = parallel to wrist pin

Skirt | = 3.619, - = 3.605
between rings 1 and 2, | = 3.604, - = 3.603

Then I got out the Elring headgaskets that I got 3 of for $5 (plus shipping).
The cylinder sealing rings (metal) exactly fit over the tops of the pistons,
no interference and no apparent clearance. Uncompressed thickness of these
rings is 0.035" so I suspect that they compress to 0.032"/0.8mm

My conclusion is that if the overbore is exactly concentric with the gasket
pattern, and there is no throw of the pistons above the deck, these gaskets
would be usable as high-compression, big-bore gaskets for STD 2130 size,
not for overbore above the 2130 size.

Is this a call to "blueprinting"?? Or maybe a very slight chamfer to the top
of the piston?
--
George Downs, Bartlesville, Oklahoma, Central US