Alright, so the 300d's turbo kicks in around 2200rpm or so, and power doesn't really do much past 3500rpm or so...

So what's needed to have power increase a little past 4k rpm?

What's restricting what? I want a stronger top end.

I feel like the stock power band is basically 2k - 4k rpm, and thats generous... with it falling off toward 4k. I want the power to build to 4k+ then fall off.

Im willing to experiment and see what happens.

Ive got a healthy, stock, daily driver 1983 300d that makes good power and sounds good, but id like it to do more without upgrading to take more boost or replace it with a om606 or small block Chevy. i dont want to degrade the engine either.

Yes i know the om617a isnt built for speed, and has many things against it in that pursuit. But a healthy om617a certainly has potential, and doesnt need an upgraded/rebuilt fuel pump to yield modest top end gains. There's got to be inherent restrictions that can be addressed.

Thoughts?