I had a '94 Crown Vic Interceptor that would run consistent 16.8's all day long. Wasn't anything wrong with it ... except for the fact that it weighed something like 4,300 lbs. ...
Yeah, 16.8 is horrible. My previous '89 notch would run consistent 15.0's with a T-5 and 3.08's, and nothing done to it except an off-road H-pipe ... and I was (and likely still am) a crappy 1/4 mile driver. With a stock AOD at similar altitude, even with the granny gears, you should be turning in high 15's. Everyone's pointing to the gears, which obviously aren't big performers, but aside from that something else is VERY wrong.
First off, the aforementioned tranny issue ... whatever issue it is you're having. Fix dat. If that isn't the sole cause of your woes, give it a full tune-up (plugs, wires, cap/rotor, all filters/fluids, clean EGR/IAC/TB/MAF, check timing), check for leaking vacuum hoses, and maybe even a leaking intake manifold gasket.
Iron out the basics and you'll likely feel a huge difference. Only when you're sure that everything's peachy, THEN you should give the track another try and see what kinda times it pulls. Rule of thumb (for me) about hitting the track: If the car isn't running at 100% to begin with, hauling it down the 1/4 mile is just asking for embarrassment (or for something to break). Good luck!