We have a 2010 drx50 which is mostly stock other than clutching, jetting. I purchased a 90cc hetrick ported engine with a brand new gen 3 pipe and a new 28 pwk carb. I am wondering if I should make the 50 motor into a 70. Hotquads have a great deal on right now on a 70rt kit with pipe and crank. We do endurocross racing which is mostly flat land/woods/small mx track and we ran his 50 this year in a class with all 90cc four strokers like the ds, outlaws, lt80s etc which we finished 4th in. he needs and is ready for more power for next season. I am wondering if I should put the 90 aside for a few years until he is ready for it or sell it, or is this rt kit going to be just as quick or maybe quicker than the 90 I bought. My boy just turned 7 and is pretty small, good rider but small. Will I be able to use my stock stator with the Kiesler pro race 85mm crank that comes with the rt kit? Any advice would be great, I have a $2000.00 budget for the drivetrain. Thanks guys