I'd have to look and see how many hours are on my 582 cub, last new mower/garden tractor my pop bought back on the farm. Mowed ~5 acres every week till we moved off the farm, + plow/till the garden. Had several other mowers with them too. Current mtd junker has a newer 18hp on it. Basically no hours on it though.Yea, its got the famous top main "chuckle" at low idle that is caused by not enough oil splash from low idling, which makes sense because my grandfather babied everything mowed at a fast idle with it its whole life. I just try to always have it running at 1/4 throttle if it idles for extended periods. If it blew up tomorrow I couldn't be mad, 2000+ hours on a splash oil air cool flat head is pretty dang good and I don't think it would be worth an overhaul, so I'll probably just run it till it lets go one way or another. I have 2 other just straight MTD/Lowes lawnmowers, not garden tractors, that have the same engine that ran great till the transaxles grenaded, so I have some immediate spares.
They used to be under $200.00 in parts for new rods, pistons and all the gaskets/seals. Haven't thought about rebuilding one in years now. Still have a few spares tucked under the skid rack just in case. Truthfully I've had more issues with the kohker kt17/19 engines then the Briggs. The 782 cub I have got it's third and final transplant/upgrade to an m18.