Dear aspirant, for sastra there is no cutoff and no minimum percentile required. It is based on 12th percentage and jee main marks(sastra will calculate like this 12th percentage * 0.75+jee main mark * 0.25)

Total is of 165 marks. Out of 165 marks what are your marks based on that they will give the seat. Therefore there is no minimum percentile you need. However, you need to score good marks in both (12th AND JEE MAINS). There are 351 CSE seats so you need to get rank under 351 when marks are calculated out of 165. There is no reservation on the basis of caste at SASTRA University. The only reservation you can get is through the local category. However, there is a 'Trichy quota ', a 'Thanjavur quota ', and a 'Tamil Nadu quota'.

Hope, it helps!