Outer Limits 4x4 Board

I bought this a while back to fit to my Jeep camper with a 6bd1 Isuzu. From memory it's designed for a late model Patrol.
Is anyone familiar with which openings on the vacuum pump are for what?

A. Large banjo at the bottom left
B. Small pipe at the base of the banjo
C. Threaded hole at the very bottom (I've got a bolt in it for cleanliness)
D. Flanged pipe at the right

Large banjo is your vacuum hose, threaded hole is oil in, flanged pipe is oil drain
Small pipe is another vac line

Super. Thankyou.