Stock 4G63 can rev to 8500-9000. Modified engines go up to 10k on steel rods. Just how much higher do you want to rev?
In my book 8k is high reving and I know the 4g63 can do it (I have had a few nice pull, flowing 70 lbs/min at 8k with my donor). The idea of the k20/24 build was more about having a good NA option rather than reving beyond 8-9k.