Wanted: Rev Limiter

[ptimmerm at mashtun.JPL.NASA.GOV]

Can somebody give me a quick tutorial / goto
on rev limiters.  I broke a vavle spring in my 
323 GTX this weekend running it up past 7.5 K once
too many times.  I want to add some safety for my motor.
It is a 4 cylinder turbo motor from mazda.

paul timmerman