My new question is where exactly do you find the factory specs and/or the club established acceptable dimensions for rods? Particularly, are there any factory specs for Miata rods? I would think the following excerpts would be applicable to rods since I find no specific mention of them elsewhere:


Stock replacement parts may be obtained from sources other than the
manufacturer provided they are the exact equivalent of the original parts.
The intent of this rule is to allow the competitor to obtain replacement parts from standard industry outlets, e.g., auto-parts distributors, rather
than from the manufacturer. It is not intended to allow parts that do not
meet all dimensional and material specifications of new parts from the
manufacturer.

All engine components not otherwise listed in these rules shall
meet factory specifications for stock parts. Where factory
specifications are absent or unclear, e.g., cylinder head thick -
ness and/or combustion chamber depth, etc., the Club may
establish an acceptable dimension and/or allowable tolerance
from stock.

So where do I find the factory stock specs for rods and/or the club established acceptable dimensions and/or allowable tolerances?

If there are no specs for rods, then I would think you could use aftermarket rods - provided they are the same length and don't provide any mechanical or performance advantage - only a reliability advantage.