l.t., 245, and the rest of the guys are right. We're all assuming you mean top speed and not stop and go grunt speed i.e. off the line.
like another guy said - it's gonna take you a while to get there - especially since taller gearing doesn't help you off the line. Is that worth it to you? I'm not trying to sound like a jerk... but are you racing someone or you just want to go mph faster?
Bang for your buck a slight head mill and mid range port job would go perfect with the pipe you have and make a world of difference... I think you'd be super happy.