68Nova nailed it, it's the cam profile.
Have you ever rode a Kawasaki Ninja? When you hit about 5 grand on the tach, you feel like you've been hit from behind, the motor goes monster on you. You better be ready for the take off, the first time I did this I was not ready, I had to pull myself forward on the seat so I could let off the throttle. Scared the crap out of me the first time, the second time it was a thrill. The cam I just yanked from my coupe had the same profile but I didn't build the car for speed, I wanted more low end torque. What you have would be great for circle track racing or drifting where you want to keep the R's up high.
"When I was younger, I could remember anything, whether it had happened or not." - Mark Twain