SilverM3:

I used this motor (12-3CT)for the nats last week. It has a large power window and easily made time despite not being fully broken in. Comparing it to OS Speed motors at the track, this motor had better rip at the bottom and mid range but lost out a little in the top. I was geared for this and didn't have time to experiment with pipes. On top of the great power and mileage this unit gave me, after a gallon or so of fuel, the motor could still use some running in. I predict this motor will last quite a while. Hope this helps.