The "old mushroom principle" keep em in the dark and feed em manure ..... Darn pic's are so dark I can't see anything of the stands. Looks like those rockers are just held in place on the shafts by a miracle, but you mentioned the "stands" hold them in place. Sure would be nice to see the stands by themselves. One thing's certain if they're feeding oil through the pushrods the shafts can be solid so that could add an interesting percentage more strength over hollow shafts..... Maybe 20-30%?..............
Ive never known and always wondered if the old Harland Sharps, Dove's and even Crane "Gold" rockers were from extrusions?.... castings?..... or billets?.....anyone know?