Hey all,
Just got my GTO on the dyno and was kinda shocked at the power curve. The numbers themselves don't concern me, but I've never seen a dyno graph look like this. My tune and scan of the pulls are also attached. The power seems to be falling off BAD after 6200 rpm. All my relevant mods are in my sig. I'm thinking it might be valve float from either weak PRC dual springs, these comp 1.75 roller rockers, or a simply the AI 243 heads not able to keep up, maybe a combo of all three?? The springs are about 4 years old 25k miles, the lift on the TX Giant cam is around .640 with the 1.75 roller rockers. The springs are rated to .650
What do you guys think?