drain plug for 8 3/4 housing

I have done this twice, no issues. It's just an 1/8" pipe plug, which is fine thread. Put some thread sealant on it and install it.
The OP already ordered a kit, but now, after drilling the hole, will have to clean the inside of the housing of dripping oil so that he can weld the bung on, then repaint it.
It really doesn't need the bung, really.