An IIT background does serve as a strong qualifier at most big B-Schools. However your acads will be seen in light of the other candidate profiles and the trouble with the IITs is that there is a clear benchmark for admission committees i.e. GPAs of other IITians who are applying (and there are plenty every year, expectedly). IITs are some of the few Indian institutions that follow a well established benchmarking system and this helps the B Schools.
Your score should serve you reasonably well if you can establish reasonable differentiation. Don't ignore the other aspects of your overall candidature. Academics will only be a small though important part of the application.
Hope this answers your query.
Wish you the very best in your academic endeavours.