One thing that you are not thinking of is thermal expansion. When these components get hot, they expand, not shrink. The cylinders get larger, not smaller. The pistons, being aluminum, grow more than the cast iron block does, so you do have some reduction in piston rock to some degree, but all dimensions of the piston expand along with its diameter. The pin bores gets larger, the ring grooves get wider, etc., all concievable components grow and expand from the heat. The rods get longer also when they heat up, and possibly stretch as well. When exposed to the near 1000°F combustion chamber temps, aluminum can have an expansion of 1/32" of an inch, compared to what it mics sitting on your workbench. It doesn't have to be race type engines at racing RPM to have these problems, i've seen many stock rebuilds experience damaging results because of trying to run the quench too tight. As far beyond what I would consider a safe margin of quench as you are right now, i've seen similar engines have the closing of ring gaps and beating the bearings out at break-in RPM before they could even shut the engine down. Just trying to keep you from tearing up good parts.....Your just so far beyond the safety net, I hate to see you have problems needlessly.
