Dear SirI expecting my son to score 475/500 with 90+ in MPC at +2 CBSE . He belongs to GEN quota. What should be his minimum JEE advanced score to get into top 7 IITs

Hi,

JEE advanced rankings are independent of you boards score.
So dont relate them.
In order to get top 7 IITs and an good branch you need to have a rank below 3000.
Check the marks against that rank, and you will get an idea of what marks you are targetting. Any rank under 1500 is considered excellent and will land you in a very good branch at top 5 IITs.
Aim for that.

Best of Luck !