02-35GD-2 R-1820 Service instructions (1946-02-01)
02A-35GK-4 R-1820 IPB (1961-07-01)
Wright R-1820 factory operation service manual (1943) for C9GA, C9GB, C9GC
Note that Log in | AirCorps Library added a bunch of R-1820 manuals this week.
I am not sure if non members can see the list so here is a screen print.