^^^^^ It's hard to say, I've seen some with 20,000 without an overhaul.
The maintenance makes a lot of difference and how hard they are pushed.
The 7230 had a head gasket start leaking last year, so we pulled the head had it gone thru,
seats cleaned up and new guides. The engine will use a couple of quarts of oil a hundred hours when
worked hard on the chopper or doing heavy tillage, but still runs good.
The 1066 and 4430 have been gone thru, they were done before my brother got them for the farm,
they both came off the local tractor pull circuit and actually got turned back done a bit for using them for work again.
The 560 and 400 have been majored once before. The 8000 is tired but still a good worker for lighter jobs.
The Puma and T6050 should go close to 20,000 before needing an overhaul.
Makes my Branson with under 700 seem new still. :thumbsup: