Sprocket gearing help

[Ou812cd1]

Another newbie question.... Looking at getting more speed for my sons Honda 300ex. I've installed a HMF completion full exhaust jetted his carb witha .125 hex jet and have a K&N filter, also installed a stage 3 rev limiter. The front end has been replaced with 400 a-arms and 450 shocks with new American Star tir rods. Looking for some guidance on what I can do to his gearing now. He has the stock 12/38 sprocket installed now and wondering what other pairing would help him with a little more speed/power. Any thoughts or experiences with the gearing? He'll be racing Hare scramble events a couple more years before he moves up to the 450 class due to his age.

Thanks in advance for any advise.

[TRXASAURUS]

I would say go to a 13 up front.  Make sure case saver still fits.   Or a 37 in rear.

[z400250]

Gearing is only gonna get you one or the other ( speed or power ) 

One tooth on the front is equall to about 4 teeth on the rear.

if he isn't maxing the r's out in 5th gear the majority of the time I would say drop down one in the front, If he is riding most of the time pinned out in 5th then I would go up in the front one tooth!

[Ou812cd1]

Sorry that was a typo on the stock gears it's actually 13/38.
Thanks for the clarifications!!