Hello aspirant, your chances of getting into IITs can be assessed by following the previous year's cut off trends in Mechanical engineering.

Following are the previous year's last cut off patterns:
1. IIT Delhi - 570 (2018)

2. IIT Madras - (based on various M.Tech programs) varies from 739 - 803 [2017],
752 - 832 [2018]
https://engineering.careers360.com/articles/gate-cutoff-for-iit-madras

3. IIT Bombay - 540 ( 2018)

4. IIT Kharagpur - (depending upon the course) varies from 761 - 779 [2017]
https://engineering.careers360.com/articles/gate-cutoff-for-iit-kharagpur

5. IIT Guwahati - (depending upon the M.Tech course) varies from 550 - 719 [2017]
https://engineering.careers360.com/articles/gate-cutoff-iit-guwahati

6. IIT Kanpur - varies from 738 - 769 [2016]
https://engineering.careers360.com/articles/gate-cutoff-for-iit-kanpur

7. IIT Roorkee - 65.27 marks

8. IIT Hyderabad - varies from 736 - 740 [2017]
https://engineering.careers360.com/articles/gate-cutoff-for-iit-hyderabad

9. IIT Indore - 693 [2016]

10. IIT BHU - 734 (2017)

11. IIT Jodhpur - 56.25 [2017]

12. IIT Mandi - 578 (2017)

13. IIT Gandhinagar - 360 [2017]

14. IISc Bangalore - (917-839) [2018]

15. IIT (ISM) Dhanbad - varies from 487 - 609 (2017)
https://engineering.careers360.com/articles/gate-cutoff-for-iit-dhanbad

Now, you can atleast predict this year's trends. And you have chances of getting into IIT Gandhinagar, IIT Delhi, and IIT Bombay.

To get a more accurate prediction, visit the college predictor link given below:
http://bit.ly/2J9S0MN

All the best!
I hope this helps.