build sugesstions

alright folks, i am finally gonna be home next month. I would like to finish up my sons blaster. While i was home on thanksgiving i put the vitos prted piston, vitos hi comp head gasket, fmf sst pipe, vforce reeds, oil injector block off.

Thinking about porting or getting hte head modified. What are the pros and cons of each plus what kind of gains should i expect. He races Flat Track and TT. Also this machine sees a fair amount of dune time.

Also what carb should i be running. Its is stock right now with the exception of the aftermarket cap to allow him to run a twist throttle.

Gearing- i changed the sprocket to the 14 while i was home for thanksgiving. Do you have a recomendation. the 14 is too short.