Mercruiser 357 Mag Bravo 4V
These have 6 drain plugs in case anyone is wondering.
Two on the block itself, low on each side.
Two under each exhaust manifold.
One on the starboard side, it drains the large host going to the theromstat housing.
And one under the port side, where the water hose turns into a metal pipe, drains that line.
Unlike the Mercruiser 350/5.7L which usually have only 4.