A V8 W126 with an original chain at those miles should have it replaced immediately, along with the guides. Its a time bomb at those miles. Ideally they should be replaced every 100-120k.

On hilly roads you'd get annoyed by the M103 in a W126.....its a revving engine....not big on torque....up in the 3000-6000rpm range its a blast, and can move the car very quickly.....but on takeoff and around town it does lug a bit. In the 300E its not an issue as its quite a bit lighter....but the W126 is heavy, torque is needed.

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-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)