Small Block Intake

I am running a 360.. Stock Bottom end, Aluminum Heads, Whiplash Cam, Long tubes, 3:55 gears with a reverse manual vb.. Currently i run a Edelbrock Performer intake, with a Edelbrock 1406 Carburetor./. the Performer seems to lose steam quick.. is there really a difference between the Performer RPM and the Performer RPM Air Gap? looking to upgrade intakes and maybe add a Holley 670 Street avenger? Just a street car..View attachment 1715757359
HR mag did that test. 2.1 horspower difference.