F4B intake question--strange looking intake verses ones on e-bay

[pazcarguy]

I have been looking for an F4B intake (e-bay etc) and have found one for a decent price and the water jackets are really sound, no stripped pipe threads etc. The question I have is that everyone that I have seen has two oval slots under the carb (one slot for primary and secondary on left side and one slot for primary and secondary for the right side) The one that I can get has 4 holes other than 2 slots. These are actual cast holes and not the gasket. I believe it is original as the casting states F4B. has anyone seen this and what are pros and cons of this verses the 2 slots? Brian

 

[rbohm]

the two slots increase plenum volume which allows for better higher rpm breathing over a 4 hole opening. the difference is relatively small though, but if you build the engine right you can take advantage of the larger plenum volume. a pic of the two different intakes would be nice though to verify that both are F4B's.

 

[Helmantel]

The Shelby and Cobra versions of the same intake also came with both oval and round holes. My Shelby version has the oval holes.

 

[D.Hearne]

If you're not particular on brand, Ford Racing's current A321 intake is the same casting as Edelbrocks F4B.