Rakesh first of all congratulations for such a good score. With this score, you will really get a very good rank and if I say honestly then no-one can actually predict your rank because it is a total relative phenomenon which depends on your performance and also on the performance of other students giving exam in your category. That is why every year along with the cut-off, the marks to rank scenario changes.

Still, as you want to know a range of your rank so I will tell you according to last year scenario with 200 marks your overall rank will be around 6500 and your OBC category rank will be around 1000. But as I said above this rank can move in either direction up or down this year. Seeing the paper difficulty and student's response in comparison to last year and I think your rank will improve and your OBC category rank will be under 1000 which can definitely fetch you a good stream in one of the old IITs.

Feel free to ask if you have any more queries. All the best!!