Well, the 235 rocker assemblies are nearly the same from '54-62. On early '54s, two of the rocker arm mount bolts had studs sticking out above two rocker mount pedestals, to mount the older-style 2 bolt valve covers. '54 to '57 used a oil feed connector that had a loop that dumped excess oil back onto the head. '58-62 used a crimped style oil connector that did not vent excess oil, and may oil the rocker shafts a little better. The pedestals, shafts, rocker arms, locator springs and washers should be the same from '54-62. The assemblies were the same regardless of solid or hydraulic lifter useage.
There are a few places on the assemblies to check for wear. One is the rocker arm adjusting balls. They are available from Egge machine. The next is rocker arm faces where they ride on the valves. These can wear divots in the rocker face and on the valve stem tips. The third is where the rocker arms pivot on the shafts. The slop can cause erratic valve adjustment and noise.
New rocker arm assemblies are available from NAPA for 140 bucks. But you must change the rocker adjusting balls, as they are not hardened. Get the hardened ones from Egge Machine.
Good luck
Chip
