BL e-revo gearing

[steveo]

just got a used e-revo and installing a 2000 kv rx8 truggy motor and 4s hyperion batts, the current spur gear is a 54 but the motor is a little large and my 18t pinion will not mest because of the esc and shock holders, so lookin to get a larger pinion depending what the local hobby shop has lets just say a 68t thats what is in the brushed version, what size pinion will get me around 45mph