can you raise the redline of an engine

To be serious for a moment, usable power is a factor of cubic inch, ports, cam/ valvetrain, and intake/ carb. To shift the power curve higher in the rpm range you would need better flowing heads and or a different cam. A factory Mopar small block should be good to 7K with attention to detail and all the good parts. The 383 HP uses the same heads, cam/ valvetrain as a 440. All things equal the 383 will make peak power higher in RPM than the 440.