can anyone tell me where all the drain plugs on a inboard 5.0 mercruiser are located?

Question

i have found each of the brass couplings on the both sides as two and one in front by the water pump
where else?

Answer 1

that should be it, and these are the block drains you are talking about.

Answer 2

You will have one on each manifold and usually on each side of the block. There will be 4 total for the sides and one at the pump

Answer 3

the bottom of the exhaust manifolds. follow the hoses underneath them.