Thats a fairly nice engine characteristic. The torque at 3000 rpm aint that impressive as you may sound it to be though.

The fact is that the superchargers of today, are FAR mor efficient than the old rumpy rooters. Do a quick search on lysholm?

There is a clear advantage on high output engines to employ compound charging.

EDIT: Saw your post on hilmerssons manta, he uses an old type rooter, Eaton M62, to be precise. Not very efficient stuff as it comes to volumeric efficiency.