Now for getting NIT or SPA, there are certain criteria to be checked- your category, if this is your home state or you are applying through All India Quota, the cutoffs will be different. Only a few NITs offer B.Arch so there are less number of seats. Usually, NIT seats are filled within 3000-3500 rank in All India quota, while the Cutoffs for School of Planning and Architecture campuses are even higher. SPA Delhi seats close within 500 rank in general category, SPA Bhopal within 800. Try to score at least 97.5 to 98 percentile in Jee Main Paper 2 so that you can get into your desired college. Having said that these are based on last year's data and the cutoffs change every year. You can check past few years' cutoffs here
http://engineering.careers360.com/articles/jee-main-cutoff-for-b-arch-b-planning