1950-58 235 rockers will all interchange.
The only difference is the rocker supports.
The 1950-53 bolts that hold the rockers to the head are shouldered bolts and the supports have a larger hole in them for the shoulder as do the shafts.
Starting in 1954 the shoulder bolt was dropped and a smaller hole in the support and shaft was used.
It is no problem using the earlier supports on the 54 and later engine. Either use the shouldered bolts or just split one rocker support on each shaft so it pinches down on the shafts to keep them from moving
Sample. Chevrolet even sold this style of split support as a replacement
Sample In fact I do this on all of the engines I work on no mater what design to prevent shaft movement.
