High mileage 117 engine

[pmckechnie]

I would just like to now what is considered high mileage on a 117 engine. In other words, at what mileage do you consider a 117 done for. I know that the service it received governs how long it will last. I ask this question because my 84 500SEL just went over 300K. It runs great, will get 20+ mpg on the highway and 15+ in town, uses about 1 qt of oil in 1k to 1.5k. I just did valve guide seals and replaced the upper timing chain rails and pensioner and only had about 2 deg of stretch on the chain that has about 80 k on it. I haven't driven it much since the seals were replaced but it looks like the oil burning has improved.
What do you think about the 300K? Can I get another 100K or more out of it? My 91 2.5 diesel has 324K now and uses about 1 quart between changes. In other words, I never have to add oil.
Trivia, the 500 has 301K, the 124 2.5D has 324K and our 94 C1500 V6 has 298K. that comes out to 923K all together. 1,000,000 will be here before you know it.

Thanks

PaulM