Hey Anjan.

Here is a list of all the AIIMS Institutes and their respective cut offs for the previous year. You would require a rank around this range for a fair chance of admission here. Chances seem to be on the lesser side. But cut off varies each year due to various factors, so you can try till the last counselling.

All India Institute of Medical Sciences, New Delhi 53

All India Institute of Medical Sciences, Bhopal  647

All India Institute of Medical Sciences, Bhubaneswar 542

All India Institute of Medical Sciences, Jodhpur 459

All India Institute of Medical Sciences, Patna 1222

All India Institute of Medical Sciences, Raipur 1,145

All India Institute of Medical Sciences, Rishikesh 769

All India Institute of Medical Sciences, Nagpur 1324

Best of luck!