reducing the rev limiter will help protect the motor but only if your wife / buddy borrows the car…
this is why some tach’s have a backlight that changes colour to yellow and then red for a shift light…
if you are pushing your motor that hard…pay attention or buy an automatic…
there is no safe way to seriously increase hp and race and protect your motor without a stupidly expensive computer with a voice to say
“danger will robinson…danger”
or some kind of cruise control type system to kick in or a throttle position stop…but this sucks as, in different gears etc your throttle position doesn’t = rpm’s