Hello,

You have to score above 270 if you belong to general category to get 1k rank. If you belong to other reservation category like SC/ST then a score above 240 will help you get that much rank. SC/ST have high reservation factor than OBC in rank so it will be easy for you.

Prepare accordingly and give your best in the exam. On the part of rank , you will get a rank based on your performance. If you score high less candidates will be ahead you and your rank will get lowered with high percentile.

Hope it helps!