FUEL PUMPS

if you were reading fuel pressure close to the carb your problem isn't fuel flow restriction. If the flow is cut back the pressure would drop off.

Could you post a picture of the plugs? I would like to see them.

What kinda of fuel are you running? If you aren't running race fuel, Try some race fuel and see if the problem goes away. Or if you don't have any race fuel add some toulene or xylene to increase the octane of your pump gas. Mix 10to1. Toulene is 120 octane.

Have you checked your timing at 6200+ rpm? Try that and see what happens. If it goes crazy at that rpm then could be a number of things Pick-up coil, timing chain etc.