we vannot predict from the score bevause The scores might be change depends on the Difficulty level of paper,Number of applicants and Normalisation..

But if your Rank.is below 1000 in JEE advance merit then I can assure you that you will get top 3 field under OBC category.

According to 2018 Cutoff Rank In OBC is

Computer science-145-311

Electrical Engineering-570-920

Mathamatics and Computing-688-736

Mechanical Engineering-762-1250.

For more Cutoffs and previous years scenario Please Follow the link.

https://engineering.careers360.com/articles/jee-advanced-cutoff-for-iit-hyderabad/amp