Assuming you're running a Honda or one of the multiple ICC/KZ Euro motors, just change the driver. On many/most occasions when we were fine tuning a ratio, we'd change both the driver and axle gear. EG: 19/23 = 1.210, vs 18/22 = 1.222, vs 17/21 = 1.235. Road race gearing obviously.
As I recall when we were sprint racing the largest axle gear we had was a 28. And dropping one tooth on the motor is makes a huge difference.
Have fun,
Clark Gaynor Sr.