Hi dear,

             Yes you can get seat in NIT Silchar with 7400 rank in JEE mains 2018 under OBC category in mechanical engineering easily.Previous year Opening and Closing rank for mechanical Engg. in NIT Silchar is 

Mechanical Engg (OBC-NCL)

For Home State quota

Opening rank : 9534

Closing rank :22470

For Other State Quota

Opening rank :4959

Closing rank : 8220

All the best