Psssst,,,,G.R. those "old" Chevys your talking about that are still on the road have a 1955 or newer 6 in them! The venerable 235 cid Chev 6 was a workhorse and very reliable motor, circa 1955 until 1960 something?
Before 1955 or so? The rod bearings were "poured" or "cast" of a lead like material, they were not "inserts" like ALL motors have had since 1955 or so. "Babbit" bearings they were!
Pre 1955.....
oil pump in the Chev 6? We don't need no stinkin'
oil pump!
The bottom of the connecting rod had a little "scoop" on it that "dipped" into a narrow "tray" mounted just below the connecting rod. The little "scoop" led to a hole drilled though the connecting rod so the
oil would be forced into the hole and onto the crankshaft journal. The faster you went the more the little scoop would "sling" the oil into the hole. They had NO oil filter either! A big after market add on was the "toilet paper" (literally) filter, but you knew that! LOL
Thus, "dipper rods". Now theres some "hi tech" oiling going on!
It is noteworthy that the GM 6 did have over head valves way back in the 30's however!
Ernie