The last person to get admitted to AIIMS in 2018 from the SC category had a merit rank of 688, so yes you do have a chance. AIIMS, New Delhi will declare the AIIMS MBBS 2019 cutoff on June 12 along with the release of the result after 6:00 PM, the officials have confirmed. The cut off of AIIMS MBBS 2019 is the minimum required percentage which needs to be scored in order to qualify for the exam. 

Here's a link that will help you out with the cutoffs for all the centres of AIIMS:

Https://www.google.com/amp/s/medicine.careers360.com/articles/aiims-mbbs-cut-off/amp