I can tell you my friend has a nice mild 10.5:1 306 with edelbrock heads, TFS street intake and a comp 270xe cam making nice power (323hp/348tq) His car peaks about 5500 and then drops after that. By 6000 rpm he's lost about 20hp. Just to give you an idea of the top end. An RPM intake would have been ideal for him. Anyway, with that E cam I don't thibk your gonna gain much with an intake swap and using a "bigger" intake might cost you a little under 3000. With that E cam your NOT gonna have your cake and eat it to. Do you plan on more changes down the road? Once I hear back from you, i'll help out more. Theres also soem "hidden" power in your combo with a LT and TB swap. The TFS street heat with a 75mm TB is a good choice for you if you don't have any big changes down the road. The performer is a good choice as well but more money.