It's not HP that makes you go faster, it's torque.

The main reason the 560SL is much faster is not the larger engine, it's the torque multiplication of the first gear going from 2.31 to 3.6. Even with the lower numerically rear gear the 560SL torque multiplication is over 20% greater.

Tomas, you my be correct, I have been using chassis dynos since 1968. I was fortunate to have many friends and mentors in the speed industry in southern Kalifornia. I was into small block Fords then, built a 330 HP 302 Ford, then a 400 HP 351 Windsor using Pontiac 389 valves.

Not worth a chassis dyno now, but if I take the intake manifolds and enlarge the lower plenum it might make another 20 HP. But I would need a tuner who understands the Bosch fuel injection, how many like that exist?

So for now I am quite happy with the better acceleration.