JEE Advanced maximum marks 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.

Cut off for getting IIT  general category in 2017 was more than 145.

You can check the cut off from the given below link-

IITs cut off for top branches

Good Luck!!