My 450 '72 is an american version , badged 350 SL with a 4.5
In Europe the 350SL was a 3.5, I believe also with a 3 AT.

The thought was first to have better accelerations with a 4 speed. But secondly to consume less in 4th, as I thought that a 4 speed had also a lower ratio in 4th speed ( called overdrive), so that that RPM was lower. Because at 160km/h my RPM is about 4000.

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Gregory, Belgium, Kortrijk