Sir
It is difficult to give exact Marks for eligible because yearly number of students and criteria  is changing so try your level best to get a good  college
If you are capable go with daily schedule to get good marks and good college
Thank you

Hello Sakthi,
Here is the link for the top engineering colleges in Tamil Nadu, click the link and check TNEA cut off trends about top colleges
https://www.google.com/amp/s/engineering.careers360.com/articles/tnea-cutoff/amp
Hope this would be helpful.
Thank You.

Dear sakthi ,
     It is not possible to predict the exact cut off marks for colleges as it changes every year . The main factors on which the cut off for colleges will be decided are :

1. Number of student participating and availability of seats
2. Difficulty of the exam
3. Previous year cut off trends.  

So my suggestion is prepare well for the exam according to the syllabus and give your best.

However the link for the previous year cut off for TNEA is given below you can go through it for reference .
http://www.google.com/amp/s/engineering.careers360.com/articles/tnea-cutoff/amp

All the best !