In Reply to: 2n governor casting numbers posted by chris eby on August 22, 2017 at 20:29:25:
I will have to check on that date Kirk supplied, but my data shows the oil line to the governor was added in 1944. I will have to get my cast iron 9N governors out of mothballs and check, but I believe they were supplied by NOVI and had "9NN" cast on the housing, maybe a part number too. ALL the MPC's list the governor assembly as p/n '9N-18200-B' from 1940 thru 1943. There are no MPC's for '44 and '45 years. the January 1946 MPC lists the governor as '9N-18200-C' so sometime between '43 and '46 a change was made and I suspect it was the oil line and body switched from cast iron to aluminum, but I'm spitballin' this info. I think the bodies were changed to aluminum before the war but could be wrong. 9N Governor disassembled shown. Here's a scan of my original Governor Maint'ce. & Repair manual dated 1946 -see LINK, if that'll help...
9N GOVERNOR PARTS: