I have been considering switching from my Ford Racing Performer intake to an Edelbrock Air Gap for my 302 SB with 351 heads.
Reading the Edelbrock catalog, the ports on the Air Gap #7521
manifold measure 1.04 x 1.85 inches. The ports on my 351 heads (on
302 Ford SB) measure 1.25 x 2.0 inches. The restriction would appear
to be the manifold's smaller ports. I'm not a porting expert, but is
there any value to be added by grinding the manifold ports to match
the inlet.
Reading the Edelbrock catalog, the ports on the Air Gap #7521
manifold measure 1.04 x 1.85 inches. The ports on my 351 heads (on
302 Ford SB) measure 1.25 x 2.0 inches. The restriction would appear
to be the manifold's smaller ports. I'm not a porting expert, but is
there any value to be added by grinding the manifold ports to match
the inlet.