Hey Aspirant,

First of all,  it is not possible to tell the marks at which you will get a college or secure a particular rank. Also MNNIT Allahbad is a very reputed college and it is one of the top NITs.  So according to my observations you need to score atleast 290-300+ marks in order to secure a rank which can get you into MNNIT Allahbad,  although these marks and rank may vary every year depending on the cutoff.

For your further reference I am providing you with a link to predict a college through JEE Mains rank

https://engineering.careers360.com/jee-main-college-predictor?utm_source=qna&utm_medium=jee_cp

I hope this helps !!