My 1982 Euro 500SE came with euro-logs. 228hp rating.

My 1983 Euro 500SL came with tri-y's. 228hp rating.

Not to contradict Roncollo but to clarify, more specify, the factory data states the cars are 9.2:1 CR.

This was also verifiable until recently via automobile-catalog. They have stopped publishing CR on these engines.

To my knowledge the 241hp car was a 1986+ (AKA gen II) car with KE-jet and has the better flowing intake manifold and different fuel distributor as well as EHA. (Electronic hydraulic actuator= kind of a 4 bbl for Bosch).

I personally am not aware of a 10:1 ECE/RUF 500SL making 261hp. But I am not all knowing. What a rocket ship for that time it would be. Mercedes-Benz loves to make their S-Class sedans their top speed beast. Well at lest back then they did.