how much should be my marks in kcet and board pcm to get rank below 1000 in kcet?

It is difficult to predict the actual marks to get a rank under 1000, because it depends on the various factors like number of students appeared for the exam, highest score obtained, difficulty of paper etc. Going by previous year trends, in general you should aim to score more than 140 marks in KCET and at least 95% in boards PCM to get a rank under 1000. The more you'll score, there will be more chances of getting admitted in Top colleges.