Yes after improvement you can apply for the SRM exam. The basic eligibility states:

'Passed in Higher secondary examination (10+2 pattern ) or appearing in Higher Secondary examination in the current academic year with Physics, Chemistry and Mathematics as major subjects in regular stream from any state board within India, CBSE, ISCE, Matriculation, or NIOS'

The percentage requirement is:

'For Kattankulathar campus, candidates need to have secured 60% aggregate marks in PCM, while for Ramapur, Sonepat, Vadapalani and Ghaziabad (NCR) campuses, the candidates should have secured minimum 50% aggregate marks in PCM. For SRM Amaravati campus, the candidates need to secure 75% aggregate marks in the qualifying exam in PCM.'

The SRM applications are on till march 31st, 2018 and the exams are in the month of April.

You can check the complete dates here. 

Make sure before the counselling you have your new and upgraded marks and documents with you.

Good Luck.