Oil drain plug location cc 350 v8 +

[Lococoho]

I am new to big boats and am trying to drain oil, change the plugs and replace impellers on a 1972 coho with dual cc 350, can’t find info kn the gap? Impeller location and I evac the old oil but want to drain the last bit. I’m at barkers island in duluth , would be very appreciative if anyone can offer assistance.