Edelbrock AVS2 Carb Dilemma

I agree with the 500. The stock exhaust manifolds are going to really limit how much it can breath regardless of the intake. With headers I might go with the 650 but the 500 will do everything you will need even with them. I doubt you'll spin that thing to 6k much and if you put a 5000 rpm limit in that calculator it will ask for about 400cfm.