I have a 2003 mustang gt and have been thinking about getting a supercharger. My question is how much HP can the stock internals and stock clutch handle?

 

I would not go past 400rwhp on teh stock internals. Thats about the most anyone runs without seriously worrying about it. 380 is a pretty safe number.

 

As far as the clutch, it totally depends on your driving style. If you are spending the cash for a s/c though, you might as well go ahead and set some aside for a clutch anyways. Look at it this way, regardless of how you drive or how much power you make, you WILL eventually have to replace the clutch if you keep the car a long time. Go ahead and buy one and have it sitting around for when you do need it.

As far as the internals go, there is no magic number. Some people get away with a good bit, some people have fried engines with just over 300 hp, alot of how the internals holds up depends on the tune. Dont be cheap in this area, as it could cost you an engine if you have a crappy tune. This being said, from what I have read on the internet, 400 rwhp seems to be around the limit on a stock bottom end. Like I said some get a way with more, some have blown up with less. Just make sure you have a good tune, and your fuel system is adequate and you will most likely be ok.