Brassbounder has twin Lehman 120's with over 8,000 hours now.
I do not remember the exact number because I have changed the hour meters and would have to go back to my log to get the numbers from the original meters to add to the current meters. It is now over 8,000 and I will guess about 8,300.
No major overhaul on either engine. I have replaced oil coolers, transmission coolers, water pumps (fresh and raw), starters, rebuilt an alternator etc. over the last ten years. I also replaced both heat exchangers. All the outside equipment can be replaced by yourself with a little care and perhaps a helper for the heavier stuff.
The engines are fine but now due for injectors as I have a small amount of smoke recently.
As per all Lehman's, they do smoke on startup but once warm it goes away.
I confirm the comment from Bob Smith above. He has mentioned more than once than a first overhaul around 10,000 hours MAY be necessary. I doubt I will reach that. I used to do 300 hours per year but recently I have only been averaging 100 hours per year.
Hopefully this year will be higher