There is a guy named Hermit Scott, over on sailboat owners, who is in the process of changing out his 1 GM ( I think it's a GM ) to a 2GM. He wants more power. According to him, he has just rebuilt the engine, and it runs great, but oil pressure is a touch low. I think about 10 lbs. less than what is called for. Apparently there is a bushing on the pump that wears or somesuch. Anyway he says he ain't gonna mess with it, and has found a 2GM20. Might be worth giving him a holler.