Hey.

No, you cannot get admission in Calcutta University through CLAT. CLAT is an entrance test only for admission in National Law Universities in India. NUJS Kolkata, comes under CLAT.  You would require a rank around 200 atleast for admission under NUJS Kolkata. Admission in Calcutta University is done through their self conducted entrance test- Calcutta University BA LLB. You can use the link given below for any othed details regarding this.

https://www.google.com/amp/s/law.careers360.com/articles/calcutta-university-ba-llb/amp

Best of luck