Humble opinion
 

Well it looks to me you have about 250 pounds of stereo equipment,do not worry you will out grow that after awhile,I used to have about 3-400 pounds of stereo equipment in my car.

If the motor is original,then yes it is your valve springs,if the car seems to get right at 5000rpm's and it seems like it does not want to pull anymore you have bad springs,get them out of there.

Run it once without the stereo equipment and se what it does and if that does not help then try a good tuneup.

Good luck

I take out the subs and the spare tire when i am at the track....what springs should i get? maybe just forget the supercharger for now and get heads and intake??? Or wait a while and get a crate motor?? what do u guys think?

Definitely you can't go wrong there with getting a crate motor,if you have seen any of my other post here,I always say have a plan.

FRPP has a number of different crate motors the 392,about 4 or 5 different 302 making various hp from 270-345.

Or you can go to an aftermarket engine builder like Fox Lake,USA Racing Engines,Livernois,CHP and Ford Performance Solutions,they are all good engine shops are very helpful.

Glad to see to you decided to keep your horse.

You just sold yours...?