8k rpm ...

I’ve buried a 9,000 rpm tach more times then I can count for over a decade in a 340
Dual purpose street strip car. Nothing exotic or expensive.
Only issues were an occasional broken valve spring, which meant I carried a spare, and got pretty good at changing at the strip.
Ported J heads with the .557 sold cam and a 160 pounds of valve seat pressure.
4.56 gears, and 4500 stall 3200 lb Dart in my profile