Hello aravindan,
Actually as per my knowledge, sastra university doesnot consider jee mains marks completely,it aslo considers you 12th board percentage too.
They take the 75% percentage of 12th board and 25% jee mains marks takes an average and releases the official ranks and the students who are scoring below 4000 rank may have chances to get into it.
You can check it in official website of sastra university also.
All the best!!