And where you are pointing, the HP curve is still up at 350whp. I agree exactly at 7000rpm the torque and HP fall of dramatically (i suspect due to back pressure, the hotsides face each other with a “T” shaped downpipe, and due to the 12psi - 9psi taper). But with the mountain of torque behind it in the RPM range you can afford to shift at 6750 and still be in the powerband.
You know, power under the curve. Which if you follow it, is extremely flat. Torque gets you moving, HP sustains it, ya know?