What I did on Sea Quest (E-35-2, 1972) was to saw out the old original iron pipe affair...all of it; and replaced it with a water-cooled system. The exhaust elbow is a Westerbeke unit which just happens to fit the existing flange on the A-4's manifold, and also fits under the setee without any modification whatsoever. The water exits the manifold, is routed up behind the port setee cushion back to a vented loop well above the water line, and back to the elbow where it's injected into the exhaust. The exhaust is routed back through the bilge to a Vetus waterlift device mounted transversely immediately ahead of my refridge compressor unit, thence to a Vetus riser assy suspended vertically just behind the bulkhead, and out.
This will sound complicated to all but those E-35 II owners blessed with an A-4. It is an extremely clean install...totally invisible and perfectly functional.
I'd post pics but haven't a clue how to post attachments to this site. An inquiry on the Ericson site or directly to me will get a more thorough explanation...if interested.
E-35 II, #174