Iam currently running a type 9 gearbox and a 3.9:1 diff in my live axle striker and i'm considering swaping to a 4.1:1 ratio for better axeleration. how do I work out mph per thousand engine revs in top gear? thanks m.

Try GearCalc. Very easy to use....

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What he said

[Edited on 13/6/09 by Omni]

thanks for the reply will try it later. m.

Try different wheel/tyre sizes too as you may find it impossible to find a 4.1 CWP.