When I had Harlan Sharp make a set of custom rocker arms built for my crossflow Ford they told me they used Pontiac extrusions. I had them bronze bush the pivots vs needle bearings. Roller tips.
But be forewarned it required me to make a trip to their Ohio offices with a set of blueprints of what I needed to get their attention.
You must be willing to sacrifice to have a unique and technologically superior engine. That means hours of selling your ideas and up-front work on your part.
