This probably don't qualify. My dad had a 534 ford engine on our irrigation well for close to25 years. Just retired that motor a few years back. Must have had a zillion hours on it. Avalve went out on it. Those valves were adjustable on that particular engine, The thing I hated most about that engine was the oil filter. It was a canister type located by the engine pan. Kind of messy to change. You also had to tighten the filter up just right or it would leak. A pretty durable motor otherwise. I do believe the 460 we have on there now has way more power. The 534 produced most of its power at a lower R.P.M. than a 460.