Forgive me for asking but i really do not know that much about torque convertors. It seems that people change them to get better launch times. my 1987 gta has a stock L98 with 1.75 long headers, chip, stat and fan swithces and flow master but was wounder about the torque convertor, Should i swap it and if so what type is recomended and what does all that stuff about lock up and things like "2800 stall" mean...thanks in advance.

 

Torque Converters are to automatic transmitions what clutches are to manual transmitions. A torque converter works by continuously slipping during low speed low idle. thats why you have to keep the brake on while in gear but it doesnt stall, the TC slips enough to allow the engine to idle while in gear.
TC swaps are one the last things you do to a car, you must make sure your transmition is in good shape, because you have to remove it when you swap TCs. A TC's "stall speed" is the rpm at which the TC fully engages. So if you have a 2800 stall that will allow your engine to rev up to 2800 before it fully engages and you take off.
Before you look into getting a TC you should have your car dynoed. and you should be near the end of all the engine mods that you plan. Changing an engine component changes your powerband, so thats why ppl find that a heavily modded engine works better with a different TC stall.
So before you buy your TC, make sure you have all your substantial engine mods done. Get it dynoed to see where your powerband is. Typically you will want a stall speed just a bit lower than where your peak torque is. if you launch at peak torque, your essencially launching at full power with the lag time of winding up the engine.

If you have further questions about TCs
visit http://www.calgarydragracing.ab.ca/pits.html
at the bottom there two sections that explain it very well.
Good luck