Maybe Dennis will comment on what light weight internals are forbidden in the rules for PSMCD. H beam rods are considerably lighter than a I beam rod, while they might be a little beyond the scope of the rules for pure stock, most H beams rods are not light enough I would call them light weight. They would be on the edge of what becomes light weight. A stock cast rod is right under 900 grams and a H beam is closer to 680 grams. The old early rubber rods were in between those numbers. Aftermarket RPM and Eagle 5140 alloy I beam rods are considered a stock type service replacement rod. For most of the pure stock classes I know of you can also use lighter weight pistons with 1/16” rings. But lightened cranks, strokers, different length rods, aluminum rods, and pistons with narrower that 1/16” ring would all be outlawed in pure stock.
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