Looking at the dyno results when the engine had the 650 CFM carburetor on, it's stopped gaining horsepower at 5800 RPM. then when it had the 750 CFM carburetor at 6000, where they shut off the test, it was still making power. They did not take it to its peak.
That motor is designed for more RPM than 6000 with that combination.
Probably would need some oiling system modifications though if they were going to run at higher rpm for very long.
I would probably never take it past 6 grand anyway, unless the occasional strip time. I'm looking for a really fun street car, with occasional strip time. I'll probably do a few oiling mods anyway just to make it live as long as it can.