I've got the '80 Tahiti 350 chev/OMC 800 combo, and it's run great for the last 6 years. I've changed the oil in the drive ONCE in that time, but check the level at the start of each season. I'm running stock heads, shim gaskets, Performer RPM manifold, adn this year upgraded from a 270 to a 280 cam, but didn't change the springs, so only picked up about 200 rpm. No problems, currently running right at 65 mph with a 14.5 x 21+ SS prop. I've heard from others that I'm pushing the limit, but.....