LD340 manifold vs RPM Air Gap

Hey everyone, I just picked up a brand new RPM Airgap for my 360 from my buddy for $175... YaY!!!! Yes, it's a true Edelbrock. I am currently running an LD340 on it (cracked my first RPM on install). What will be the difference in performance? any gains?pros and cons? Thanks everyone!!! Hope to see some of you tomorrow at the FALL FLING!!!!!!

Brian