I haven't run one of the CO27's but according to Eric (EAMorotsports) they're a very good motor with lots of torque. They need to be geared way up from where you'd normally gear a stock motor. I think he's recommending 3-4 teeth higher for starters.
I've heard that before with an Integy Matrix V10 pro-stock 'Hi-RPM' motor, when I tried it it was no faster than my tuned Monster.
I stuck in into my old Tekin dyno and it had almost identical results to the Monster.
Skiddins