ahh no good! we just finished up a Trick flow kit on my friends car, and we didnt tighten down the timing chain bolt, so it backed out. broke the timing chain, and bent two intake valves!
although we got lucky, it did not scar up the valve seats at all. ordered the new valves from summit, bought some valve grinding compund, popped the new valves in, spun them to make sure it looked like they would seat ok, and they were fine. reassembled the motor, and for 500+ miles now nothing has gone wrong, sounds excellent!
just take the extra time to check out the other head, if you havent already? make sure you dont have a compressed lifter, or bent pushrod?