JEE Advanced maximum are not defined :

Maximum Marks vary every year like below:

2017- 366

2016- 372

2015 - 504

2014 - 360

So, it is difficult to predict marks as exam pattern and marks change every year but you should score more than 50% marks to get good branch in Top IITs.

According, to 2017 cut off you must have secure more than 145 marks to get into IITs.

You can also check the cut off rank from the given below link

IIT Kanpur Cut off

Good Luck!!