I am reading an aem boost gauge and it tops out at 8 very close to redline, but also the previous owner gave me a dyno sheet. As for the motor, it’s an mmr800 short block, patriot stage 2 heads, cms stage 2.5 blower cam.
Does the dyno sheet show the boost? At 6500 its most likely making more than the 8psi that you're seeing at 5800rpm.