A 1954 18-bolt 235 head (high pressure 235 engine) will work on the 1953 235 engines (on both high pressure and low pressure 1953 235 engines). The 1954 head's valve cover attaches with 4 machine screws on the sides. The 1954 head's valve cover attaches with two bolts/nuts in the center/top.
The rocker arm assembles (and oiling connection) should work interchangeably (Pre '68 Dave would know for sure).
