better you have all the chance to get into this pec chd for sc category the 7th round cutoff last at rank of about 12,500 for those two branches that you mentioned ..and i think you'll be under that rank but rank also depend on number of student particularly from your category sit for jee mains and i would also like to inform you that if you are not able to secure that position go for csab round and even in that also if you can't make it go for other branch also and in college there would be a risk but chance of getting upgraded in to branch of your choice

good luck