The X suffix in "F55X" shows up as a 1955 first series 1/2 ton truck Thriftmaster 235 with standard clutch.
That engine would not be drilled to supply oil to hydraulic lifters.
Same would be true for Chenzo's 0877432 F255X (or, for any 235 Thriftmaster/Loadmaster truck engine until 1958) - is that correct, Dave?
