Originally Posted by tclederman
Late 1955 235 engines still used shims.

I'll check the 56 through 58 manuals (if no one posts the year that shims were no longer used).

added later:
It looks like 1956 and newer 6-cylinder engines only required shims if a bearing cap was replaced. Maybe someone with more experience will chime in on this one. I did not need to use shims on my 1960 261 engine.
Thanks for the reply, The reason for the bearings being replaced is due to me finding a cap and bearing in the oil pan. looks like it had vibrated loose over time. I did not find any damage to the cap but did find wear to the bearing. The strange thing is that you would never have known that the cap had come loose. The motor was running fine with no knocking. The only thing that made me check was the oil preasure light comming on at idle.I figured the pump was going out. The 235 is a amzing engine. It kind of makes you wonder why Chevy hasn't built a up to date 235.