Will i pass emissions in IL with.........

jet hot long tube headers, cat, and flowmaster muffler?

jet hot LT's require the cat to be moved and be removed. So techincally, you cant have the set up, jet hot LT's with also a cat thats in the right spot, in order to pass emmisions. FLP's have a LT that'll pass, but its like 1200

Is that the only mod's?

With a good quality catalytic converter,you should pass.

If it is one of those "catco" hi flows I have seen lots of problems with them & emission testing.

I do alot of cars for the Ill. IM-240, & seen alot.

Take it in & see what it will do.

B-4 test , in the lane inform the "inspector" you request a Pre-condition.

They will run it up on the dyno b-4 testing it.

This makes sure the converter is lit & you get the best # possible.:D

you will pass no prob unless you have a bad cat. converter, if u don't run racing fuel through it ever then it should be fine, and like he said make sure you get the converter nice and hot