i got a bulit ls/vtec with je pistons,pr3 head P&P,crower cams stage2 drag, crower valve springs with retainers,skunk2 intake manifold,aem cam gears,b16 oil pump,dc 4-1 header,p28 ecu with mugen program
fuel psi @50psi cam gear intake+2.5 ex+3
Denso spark plugs .44 gap
timing set at stock

the Problem is the start cutting power at 8500rpms it just started i was going to 9400rpms with no Problems but now i took the motor out and put new SS valves in and a new block its like it is missfireing or somthing or how the valves are adjusted what can make it do this

 

Re-adjust valves.