There was a discussion about this some time back. The advertising for 1948 Chev trucks talks about the new precision main bearings that can be replaced without machining them. According to a source at the VCCA, GM eventually came out with precision field replacements for the earlier 216s that did not have to be machined. I don't know how far back this goes but it would be 1947 and back.
You always have the choice of having the rods machined to take inserts. These are special inserts for this application.
