Question about gearing for Top Speed

AJ/FormS said
It's unclear to me what you are actually asking. Are you asking; "how fast can I go with a 340 that makes peak power at 6000rpm?" If so then you would need to know how much real power it makes up there. And you would need to know a few things about the chassis it is going into.
Power required increases with the square of the speed. So if your car takes 30hp to go 50 mph, then the formula predicts 640hp to go 200mph. To hit 200 at 6000 rpm with 28s, would take a final drive ratio of 2.50

here is the formula;
mph = (rpm x TC)/1056 x FD
where TC is tire circumference and FD is your Final Drive
Example;
200= (6000 x 88)/1056 x 2.5= 200
Below is a power curve for a hotrod 360 sorta like the one I built; with a 230/237/110 Hughes cam. You can see that at 6000 it is just beginning to slide down the backside of the curve. The point is that the 340, to peak at 6000, is gonna need more cam than a 230/237/110, lol.

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I understand the math. Maybe I wasn't clear. I totally understand that higher gear ratios (ie 2.76) will produce a higher speed at a given RPM compared to a lower ratio (ie 3.55). I was just assuming there was a certain point at which the engine would bog down as it tried to overcome an extremely high gear ratio. Kind of like trying to start out in 6th gear. Or maybe it becomes a matter of overcoming friction from wind drag. In which case, you need more HP. Just wondering.