when racing in the stock class, you have to invest in some of the best batteries and esc's to be competitive, and by competitive I mean having a chance to win.
I bet the guy you were comparing to was a local hotshoe. Either way he probably had his motor tuned up pretty well along with a high end esc.
Some of the first things you need to do with a stock motor before you run it for the first time if you want to be fast:
1 - align the brush hoods, racers edge makes a good tool, I have on and it works very well, parma has one too, but I think it is more combersome to use.
2 - sometimes the bushings are not set square in the endbell and can, press on the bushings with a wood dowel to set them in, although more than likely they already are.
3 - You need to shim the armature so the comm is in the center of the magnetic fields, this process is tedious, buy a reedy shim kit and that will tell you how to do it, it think they cost $2, very good investment.
4 - remember to be careful with your gearing selection, it is easy to overgear a stock motor. over gearing = motor death
these are the 4 basic things you should do right off the bat. the next steps involve money. well, at least more than $2.
5 - finding the right brush and spring combination is critical. I think trinity and reedy have guides on their websites to help choose the right stuff.
6 - batteries and esc. This is where cubic dollars come in handy. If you want to put the icing on the cake with all the stuff above, you should have some high voltage batteries, this is what is required if you want to go faster. If you have high voltage batteries, you would be smart to invest in a good esc, a gtx or qc2.
I didn't want to type this much, but I hope you find this helpful in your quest for more speed