"I have a 2003 Larson 330 Cabrio with twin 5.7L GL Volvo's. We started having an intermitent overheating problem on the port engine at the end of last season. As it turns out we had an exhaust manifold crack that started letting exhaust gases and cooling water to mix. it finally cracked enough this year that I got water into the right bank of the cylinders. #5 cylinder was shot! To avoid dealing with headaches I went to Detroit and picked up a Brand New replacement Volvo Long Block. My marina installed the new Long block and now at 3000 rpms the engine is overheating. They are trying to blame a cavatations problem? I think they just screwed something up in setting up the engine. Any thoughts on this problem would be appreciated. They said the impeller is fine and gushing like niagra falls, yet still getting hot at 3000 rpms."