you try rotating the thing 180 to make it work? Some of them are straight inline with the 2 bolt holes others are offset. I had a hard time finding one for our 84 at Autozone but it has a th350 in it. I ended up getting another style, one from an 85 monte carlo.
check this out...
http://www.autozone.com/autozone/par.../N-ik2xeZ6o23q
the one with the a in front is offset looking and the one ends in v is not. At least that's how they look may be the difference. You may have one and need the other.