In Reply to: timing gear cover question? posted by chris eby on October 21, 2018 at 09:07:23:
9N-6019-A and then -B were Grade "B" cast iron, starting in 1939. -A had narrow reinforcing ribs inside, while -B had 3/4" wide flat ribs were used in the -B. This may have been two different suppliers' approach to reinforcing. Don't have any evidence for the -6017 cover except for the 8N-6017-A (cast iron) and -B (aluminum alloy). They both ran from '49 to '51, and revised many times.