The V8 lineup is characterized as leisurely, with the 380SL called notably slow and the 450/560 stronger; the 560SL is cited as roughly 3-4 seconds quicker 0-60 than the 380. Some early US 450SLs are remembered fondly as fast and planted, and the underpowered feel is why one owner welcomed an LS swap.
Engine power across 280, 380, 450 and 560
Mercedes-Benz SL (R107) · driving