GMCH is a well known medical colleges in India. The cuttoff changes every year. It is quite difficult to predict the rank .But looking at the previous year cuttoffs we can make an Estimation. If you are Gen category student you need to get a rank of around 280 or less.For the OBC the rank goes upto 8000. You need to get a rank lower than this. If a person belongs to S category 33,000 is the estimated rank. YOu will have to get rank less than this to get admission in the college. 

If you need any further details regarding the college you can refer to the link attached below.

https://medicine.careers360.com/articles/neet-cutoff-chandigarh