It looks like (based on 3 minutes of research) 79 and 80 are different than everything else for some reason. I have no clue what that reason may be.
Honestly, I'd call Ace. Their prices aren't bad at all and they'll get you set up if they can. They may even be able to cross reference you into a new gas tank w/sender for cheap so you never run into this problem again. Since your vehicle says "Pacecar" I'm guessing you're not going to send it to the crusher any time soon.
'91 GT 5 Speed