On the 617 its a good idea to check the chain for stretch but they usualy don't break. After 300k miles it probably would be a good idea to roll a new chain on to regain performance.

Overhead cam V8's have very long chains, two sometimes four actualy, inline engines don't.

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2006 CL500
2009 C300 4matic
1969 280SE
2023 Ram 1500
2007 Tiara 3200