I used to over rev mine on a regular basis.

After a while, I figured out that all I got was accelerated engine wear.

Internal forces increase by the square of the rpm increase. Double the rpm and quadruple the forces. The internal stress at 8000 rpm is about 16 times the force at 2000 rpm.

That's begging for trouble.

I managed to make good power with the TT440 without revving it to the moon. 657 rwhp came in at 5800 rpm.

If you want to hit a specific mph number then change the gearing and build a stronger engine. It'll last much longer than spinning an engine higher.