Good luck with that "crate motor" guy I race with bought one had nothing but issues with it..as already mentioned what are you running for converter and gears,as far as dual-plane intakes the Edelbrock "air-gap" is the best out there..
A RPM from Edelbrock is what you want. Now, our question to you is what gears and tires do you have as well as what trans and stall converter are you running. How heavy is the car?
Also what carb & size?