What compresion should i have if i want to put a super charger on 351?

[RiCeFrYeR]

I will keep that in mind. But for now i am looking at a vortec. They have a supercharger that will run up to 20psi boost. I am realy going nuts though on this emissions stuff. I live in dallas and we have to have emissions on our cars. I do not know how i am going to do this if i go with a N/A car. I have been looking areound and i think i am going with a ford racing motor a 351 and it pushes about 400 as is out of the box and then i am going to put the charger on it. But like i said how do i get it to pass emissions test legally?