think about a diesel engine, they never rev. over 3k and alot of tractor-trailers have almost 1,000,000 miles on them and are still going. i used to drive a 1982 ford f-7000 with a walker 3208 diesel in it and it had over 500,000 miles on it and have never had a problem with it but an exhaust manifole, and doing the usual maintence.