Should I take a drop for jee advance . I have got 160 in jee mains 307 in bitsat 13000 rank in jee advance. I need mechanical in iits nxt yr

No, dont drop an year. you got good marks in JEE. Its not bad. You have still good options with you if not IIT's and NIT's. Have a look to admissions in india's tp institutes as VJIT, Lovely Professional University, thapar university, PSG College of Technology.

If you got 13000 rank in jee advance then you can easily get mechanical in some of the iits.i suggest not to drop one year.even getting into nit is far better than dropping one year as your result may go down as there would be a lot of pressure.so give preference to your branch and take admission in