Just finished building a 408w stroker carbed 750, fuel pressure set at 8 psi, edelbrock air gap intake, msd ignition 6al, msd distributor, .625 intake, .576 exhaust roller cam. timing set at 14 deg initial 32.5 advanced. idle is good and rpm is good until about 3000 then it just falls on its face bogs down and doesnt really pick back up. i have tried 3 different carbs and with no avail. msd box and distributor are new, tried different box and same thing happened. plugs are gapped at .050. Any ideas on what is causing this? Timing? Fuel? i am out of ideas. thanks guys