The longevity of ANY engine is determined more by the way it is USED and maintained than anything else. In general, lower compression lasts longer. Slower rotational speed lasts longer. Well lubricated lasts longer. This is why truck diesels last considerably longer (many more miles before rebuild or replace) than a comparable gasoline engine. This, based more on long periods at constant, relatively low RPM, more than any other factor. For typical cars, my best bet goes with the lowly 3 cylinder stick shift Geo Metro, with no hotrodding of course. My 1990 is at about 170K and still going strong. Treat this little Suzuki engine with some care (change oil and filters, air and oil, frequently) and it will last 300K easily. I have a 1968 Ford F-250 with a huge 390 V-8 which is now just passing over 300K, so even a big block V-8 can have a long life. Like I said, it is more on how the engine sees itself in life as it is used than anything else which determines the longevity. A friend of mine recently acquired a diesel generator for emergency power for his house, a small one, 15kw, used as a power source in a mine, powered by a GM 6 cylinder diesel engine. It was designed to run at a constant 1200 RPM. It was made back in the 40's and still runs as well today as it did when brand new about 60 years ago. When it was in use in a mine, it ran 24/7 for a month at a time and then was turned off to change oil and do routine maintenance. The run time hour meter said it had over 100K hours of run time. The meter only registers 6 digits, 99,999.9 before it rolls over to 0's, just like the odometer in my F-250, so who knows how many times it has rolled over already? The only reason why I know my F-250 has more than 300K is that I've owned it long enough to roll it over 3 times myself, and yes, it has lost some compression and is showing age through normal wear and tear (the vales clatter and it makes a lot of noise), but it still runs very well and on a good day, still gets exactly the same 14 MPG as it did when new. Treat ANY engine well, constant RPM, frequent oil changes and routine servicing, and that engine will serve faithfully for a very long time... unless it has some sort of built-in defect in engineering of course, which unfortunately, many engines have these days. My Geo was engineered well. My F-250 was engineered well. My friend's diesel generator was engineered well. You be the judge.