RS500 whit stronger block, was raced in about 550-650bhp, and that i consider over the safe limit, cause in racing, longevity isnt main consern. that means 700bhp is way over safe limit for 200 block.

i would say about 400 is reliable, but over it reliability will decrease. in RPM i would say about 7000 is the limit. but this is one thing that no one can say for sure how much is the limit.