To the OP....
Question...what altitude are you running at because 14.5 seems kinda low if you car is in good running condition (unless you have the 2.73s in the rear). 13.9-14.1 is common for well maintained stock LT1s.
The RPO code for the 3.23 rear end for the autos is GU5...check your door and see if you have that code...if not you got the 2.73s. If you plan on keeping your car a mild build I would definitely step up to higher gears...3.73s (will hurt the gas mileage though) or 3.42s out of a M6 f-body. BUT if you plan on going aggressive with this car don't waste money on parts for the 10bolt. Save the money and get gears when you get a different rear end so you aren't buying the same parts twice. Because when you get some more power or traction the clock is ticking on the 10bolt. They have been known to be trashed at stock power levels with the M6s. Now that being said if you can get a cheap set of 3.42s from a wrecked f-body and either do the work yourself or have it done then by all means grab the 3.42s because it won't cost you much and be good for a decent improvement.
Enthusiast is right. If I were you I would do things in the following order if your goal is 13s.
1) Maintenance...if you are still running the orginal plugs / wires / fuel filter your car is not running nearly at its potential. Btw I run the NGK TR55GPs spark plugs and love them. If you are going to spray it you will want a colder plug...probably a NGK TR6 or something in that neighborhood. Also seafoam is your friend there is a good write up on ls1tech. I have also been using some Taylor 8.2mm Thundervolt wires and haven't had any arc'ing problems with them and love them. I do know that it is hit or miss when using Taylor especially with the 8mm Spiro-pro wires...they either work very well or arc. Also changing the spark plugs on an LT1 f-body, especially with the stock exhaust manifold, is a complete PITA. Driver's side isn't too bad but the passenger side is a nightmare. I will never change these plugs and wires again myself until I am installing my headers when everything is out of the way and I can reach everything easily.
2) The fast way to drop that time condsiderably on an auto is a high stall torque convertor. You get something with over a 3k stall and some DRs and you can expect to drop at least 5 tenths off the quarter (stock torque convertor in the autos is something like a 1800 stall). However high stall + sticky tires = not good for the health of the rear. And for the sake of your trans get another trans cooler if running a higher stall. You also may need a tune for the convertor as some cars run into whats called stall wall when the convertor is switched.
3) Drag radials. My car is pretty close to stock (only a few mods) and I have traction problems on street tires. As it is on the street if am at a dead stop and floor it (not power braking) I spin all the way through 1st and well into 2nd (usually hooks finally around the 3-4k mark). This is with the 3.23 gears though and with relatively new (<2000 miles) yokohama s.drive 275/40ZR17s. My old BFGs were just as bad for this.
4) LT1s love long tube headers. Like said above either LPP or Pacesetter. Both are very reasonably priced and should net you anywhere from 20-30rwhp (ran with an ory or high flow cats).
Those four things will definitely get you pretty well into the 13s especially if your car needs some of the maintenance done to it (if that is the original fuel filter then changing this will be the cheapest horsepower you can buy). If you do add a stall convertor definitely get the DRs too as otherwise you will just be spinning a lot off the line.
So to recap:
1) Tune-up = ?? $ [?]
2) higher stall torque convertor = ~$500 [.3 - .5 tenths]
3) Drag Radials = $ depends on brand [.1 - .3 tenths]
4) Long Tube headers = ~$500 depending on brand. [.1-.3 tenths]
As far as spraying I agree with enthusiast. Some people spray as much as a 200 on the stock bottom end but I wouldn't try that for any length of time as that is asking from problems. A lot of people say 150 is ok but I would stay around a 100 shot if the motor is in good condition and you want to be safe with it. Don't skimp on the safety equipment though. Just because the system will work without it doesn't mean its smart to it. Things like a window switch, a WOT switch, bottle heater, and all the other goodies will make sure you can spray until your hearts content.
On a built bottom end you can spray these things all day with big shots and multi-stages. (over a 300 shot is common on the built for spray motors). I have a friend who ran low 10's regularly in his 1993 z28 (383 stroker + 300 shot).
Hope this helps and have fun going fast. You said the trans was built so if you already have high stall torque convertor in it I would say something isn't running right unless you:
a) are blowing the tires off in puffs of white smoke (eg a really bad 60')
b) at a much higher altitude
c) car needs maintenance
1996 Trans Am WS6 A4
Torque is your friend!