Thanks for the quick reply. I put shorty headers on it when I swapped in the 3.4 (on which I think I used the 88 y-pipe). But, I went back to stock manifolds and I think I used an 87 y-pipe from my parts car (as I seem to remember having to extend the downpipe). So, I think I'm probably currently set up for the pre-88 y-pipe. Now I'm thinking I need the pre-88 y-pipe??? If no viable used part is found, I'll see if the local muffler shop can weld mine up, and the Fiero Store will be plan C.
I forgot to mention, the y-pipe is currently out of the car.