Thanks Steve,

BTW. I had a 59 Chris Craft with twin 289s. The exhaust system had no
water
lift or a muffler.. The exhaust elbow was above the waterline (transom
discharge), however, like yours, the pipe was low near the engine and the
exhaust pressure pushed the residual water "up" the pipe to the transom
discharge. At normal draft, at rest, the transom exhaust was a couple
inches
above the waterline. I had exhaust flapper the helped keep the pipe from
filling with water from any following sea or chop when the engines were
stopped.

That is exactly my situation. The engine end IS higher than the water
line - but
the pipe it goes into is then lower. Will the exhaust pressure push that
water
"up" the pipe?