Ok, Srv's actual setup was something along the lines of: Beat up strat(#1) >Vox wah>Ibanez ts808 tubescreamer> ts808> to maybe a unvibe or somethin> to either a Fender Super Reverb, Vibroverb, or Bassman, or an old marshall (maybe).

But for you, you could some amp/effect modeling stuff. or you could buy an ibanez ts808 tubescreamer. It has a very bluesy, srv like feel to it.