Would they have also done some type of coating inside the block for corrosion?
Thats what I was guessing but not sure as they changed severl times over the years. Think just changing to a 4bbl it was rated at 235 dont think the cam was different. Marine cams are a bit more like towing cams a bit more duration @ .050 and a bit more lift. Often similar to the high speed towing grinds. I dont think I have any records as to the grind used back in those days. Mercury Marine would never divulge torq numbers.188 hp