Unable to rev to red line...?
 

I couldn't remember the last time I took my motor to red line so I thought I'd give it a go. I tried and had zero success. The revs were climbing as normal but right around 6500rpm, still at WOT, the revs dropped to 4500 and began to bounce back up to 6500. As it climbs and reaches the peak, it feels as if no more combustion is occurring.

Fully modded, PFC, rev limit set at ~8k, tuned, 5k in rebuild.

Any ideas?

maybe ignition break up, or fuel cut.
undersized fuel system for your mods?, clogged filter, old plugs/wires, dirty injectors. coils out of spec