What are you smoking?
Power has EVERYTHING to do with top speed.

Here's a little food for thought...
Aviation people distinguish air resistance as parasitic and induced drag, but the critical thing to understand is that drag increases as the square of speed. That is, while power increases in a linear fashion, drag increases exponentially with speed, in a parabolic function. For example (neglecting the effect of rolling resistance), if 100 horsepower would push a certain vehicle 100 miles per hour through the air, doubling the speed to 200 would require two-squared or 400 horsepower to overcome air resistance, while 300 miles per hour would require 900 horsepower.

Reducing drag will make a huge difference in the power required to hit a target speed. However, if you have a streamliner that's only cranking out 300 hp you're going to have a far lower top speed than the vehicle that makes 600 hp. Gearing and RPM capabilities must also be tailored to the target speed, but if your engine doesn't have the power to hit the required rpm, you're not going to make it.