will a powerdyne off a 91 ford 5,0 work on my 97 firebird lt1 if not is thier any way to make it work

 

The head unit may be the same but you'll need all the brackets and pulleys.
Even if you got everything needed it probably won't make more than 5 psi especially with a 383.
For all the effort better to find a Procharger or Vortech as you'll want more boost when you get a taste for some.

 

im running 12.1 on compression how much psi do you think i can go on a supercharger with out messing my motor up or will i have to go with lower compression pistons

 

With 12 to 1 compression I don't think you could run more than 4-5 psi.
I have the 9lb pulley and have never shown more than maybe 6.5 psi on the guage.
I put the large chamber 62cc Trickflow heads on my 350 and it lowered the compression to about 9.4 to 1.
As such I'm able to run the HPP3 timing tables without any problems.
You can always run less timing on your 12 to 1 but with a 9 to 1 ratio you could run 12-15 psi especially with water/methanol injection or an aftercooler.
With about 20 hp per lb of boost for all the effort of putting on a supercharger you're better off with a Procharger that can be pullied up to make some serious power.