331 Dyno #'s Dead @ 5100 RPM (Long)

[Fox-4-Cobra]

Timing was set at 10 degrees so the tuner could do what he wanted with it via the chip. The AFR was 13.9 according to the print off.

My post initial post is unclear, prior to 5100 RPM's the torque line was pretty flat and the HP was heading up. At 5100 RPM's the HP did not flatten out and then drop it just drastically dropped. No plataue (sp) justa rapid spike downward like it was missing fuel or air.

The rapid drop with no plataue (sp) is what confuses me. I put in a new fuel filter today and cleaned the dirty element in the MAM. I'am going to check fuel delivery first via checking the injectors. Then I'll address the air by getting a new MAM, TB and hopefully porting the lower. Then the stock ignition will be addressed.

What other things could cause such a rapid HP decline at high RPM's? I would think a need for more air would still plataue (sp) prior to falling off would that be correct?