During a web search, I found some information on Washington Irving High School, the school they used to portray Fillmore High from the outside.

http://www.preserve2.org/gramercy/proposes/new/district/40irv.htm

And here's some information about the academics of the school:

http://www.insideschools.org/fs/school_profile.php?id=956

It may not be like the IHP, but it seems to be trying.