Something else to consider that may be enlightening... If you are making 600hp at say, 6800rpm, what is that 900hp at 9500rpm engine doing at 6800? Part of the reason higher rpms make more power is more power strokes in the same amount of time. Horsepower is force over time. Does anyone have a dyno sheet that shows the power output of one of these 900hp engines at the same rpm peak of a typical multi-use 408? Yes, all parts need to work together, but having rounded power peaks rather than peaky ones is a lot harder than targeting a small rpm window to maximize output in. The PS truck mentioned does just that. The power curve of it is very high rpm and not very flat. It's not that hard to get a good idea of what the perfect setup is for a given rpm point. Its the packaging and execution, and trying to get that same perfect setup for a wider rpm band that is extremely difficult.