I think I replied on this thread when you posted your last request, but I can't find the reply so maybe it didn't go through or is floating around in cyberspace. I had my 3GM30F rebuilt this year at about the same number of hours as yours. Cost was about $3800 for the rebuild but I also replaced the engine mounts which are about $120 each; it is a lot easier to do with the engine out and damn near impossible with it in the boat. A replacement Yanmar (different engine) is about $10,000 and a re-manufactured 3GM30 thru Mack Boring about $5400+freight+installation. Contact me if you want more info.