Hi, I was wondering if knowing my engine's head serial number is useful for anything. I'm trying to figure out if my car's engine is original or maybe a factory replacement.

It's a 1992 300SD with a supposed 603.971 motor. I know those could have weak rods but my engine has 260k miles on it and going pretty strong (IMO).

The head serial number is 603 011 21 01. I don't have much history of the car. Can't find which dealer this was serviced in FL. It has records from an owner in MD - an extensive collection which I'm going to go through again.

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1992 W140 300SD
1982 W123 240D
and others non MB vehicles...