There are definitely a few engine designs out there that won the design lottery in terms of longevity. I know a guy that has close to half a million miles on a Jeep Cherokee with the old AMC 4-liter straight six, and the only engine work done other than plugs and wires is replacing the water pump at 250k. I've got ~186k on my Jeep with the same engine, and it doesn't even burn any oil yet.