Gear Ratio Speed Calculator

http://members.iinet.net.au/~wearne/...ns%20Specs.pdf

Gear ratio speed calculator .. not sure how accurate!

Using that calculator,

0.756 6th Gear
3.9 final drive.
18" rims.
8500RPM

247km/h .. reckon you would get there pretty fast with 600 odd horses though

That is on US gearbox? AU has a shorter 6th? So could be even slower.

This may also help to know how much HP you need to achieve a given speed:

http://www.apexgarage.com/tech/horsepower_calc.shtml