Originally Posted by BruceK
34s here seem to use a 380hp Yanmar. Too much power imo, unless you want to plane.
Those are the modern 34 Mainships. The 1979 era 34 was originally powered with a 160 hp Perkins. In 1980 they changed to the 165 hp range 4 Perkins. Then in 81 they started offering the 200 Perkins so it's kind of a mix after that.
Around 85 or 86 they started putting 220 Detroits (4 cycle) in them.
The preferred engine for repower was / is the Cummins 6 bt at 210/220. Some crazies like me put in more power. Some used higher hp Perkins and I've seen a few with Yanmars. The highest hp I have heard of was 315 Yanmar.
Some have used alley engines but I think that ruins the boat.
I know after I repowered it was a much better boat and much more efficient.