i have a 1987 iroc, does anyone know if a 40 series muffler fits on my car?

should. but what are you trying to do? is the muffler a single in and single out? or is it a single in dual out? if its the dual out, its a tad more difficult. That is why they designed the 80 series. But a single in single out should be no problem.

I think it is applicable.