exhaust starts as 3/4" coupling flattened to a oval to match exhaust flange then reduced to 1/2" then reduced to 3/8 and exits thru side of boat where a existing 3/8 hole was
i haven't ran motor in boat yet waiting on flywheel.
this boat is just for fun i have three airboats that i run Dumas Big Swamp Buggy with asp .46, alligator tour airboat that is getting 4" added to width and a 24" scratch built with a fox .25