Another change- - - - -mid-year 1955- - - -the shape of the oil pan rail on the passenger's side got a slight offset at the middle of the block to clear a larger oil pump- - - -the Melling M-45 or the OEM GM equivalent. There were also a couple of variations of the pump pickup screen and the baffles in the oil pan. I'm trying to help a local machine shop sort out some of those differences because an engine they're rebuilding has a Swiss cheese oil pan bottom.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!