well
i have reved my h22a1 into 8000 under full throttle, probably around 8200, the ecu sets revlimit based on several "engine load variables" technically speaking...basically means intake air temp, knock, ECT, etc, etc.

the h22 peaks around 6800 in HP, and starts to lose efficiency drastically after 7400. of course that all depends on your cams, since your cams determine where your engine makes peak HP, as well as how well it breathes at certain rpms.

regardless tho, rest assured there is a ECU determined revlimit somewhere between 7500-8200. so you dont have to worry about blowing your motor.
on a sidenote, ive heard of a stock h22a hitting 8500 without any head damage. of course i can NOT recommend your try this. (assuming you chipped your ecu, OBD1 only anyway).

lastly, i have unfortunately hit about 11k+ rpm's in my h22a1 ONLY ONCE, when i hit 2nd gear instead of 4th under WOT. luckily there was no evident damage, and that happened about 30k miles ago (64k on it now). so basically the h22a is a pretty strong motor, the weak point being the head.

~kris