Why not just change the final drive ratio ?
Go for acceleration rather than top speed.
I have a 2 litre Silver Top built by Dunnell Engines pushing 180 bhp on twin 45 webers.
All the brakes and suspension have been uprated.
The gearbox has sprint ratios making it quick off the line and mid range acceleration.
I have had it up to 110 mph but my common sense says slow down !
Wouldn't it achieve the same thing to drive around one gear lower? Just use 5th for m'way cruising. Save a packet too. (But not in fuel obviously!)
