Hi Shubhanshu.

Yes, you can get admission in IIT with a rank of 1421 under SC category. But, chance of getting a core course in old IIT is less. For that, you'll have to go for new IITs. And also, you can get 5yr Integrated Dual degraa courses in old IITs.

You can check the cutoff here.

https://josaa.nic.in/Result/result/OpeningClosingRank.aspx

Good Luck.