Sounds like my '91 350 SDL at 127K miles has a limited lifespan even though it is not burning any significant amount of oil, has never been overheated, and continues to run great. Are there any tests I can have done to birddog any potential problems with this engine? I was hoping to keep this magnificant road car for at least 300K but it doesn't sound possible from the entries in this forum and another forum that I frequent.