For Professional Mechanics Only!!!
 

How much does a completely stock 1998 Gt automatic transmission handle? RWTQ and RWHP Up to how much horsepower should i consider modifying my trany>

depends on the weight of the car and gearing.

Also depends on the way you drive it, how many miles are on it, how high you're reving, etc.

Well it all depends on what you are going to do. I mean it should handle anything N/A.

so as you can see by the responses above, this is kind of a bogus question. there is NO way to say that X power will blow your tranny and X-1 won't. If you're planning on beating the thing mercilessly, then there's no safe power level, if you're planning to just drive fast, then you can see over 400hp/tq with little ill effect. More power = faster wear and bigger broken bits but it doesn't tell you when or why... that's only possible with failure analysis. With a NA pre-99 gt, I wouldn't spend too much time fretting about anything if you're a responsible driver and you know how and when to be agressive.

Get a tranny cooler and you'll extend the probability of it surviving long term abuse.