For one thing the Edelbrock Dual Plain Air Gap is the Same Height as a Performer-2 & RPM, You can check the Edelbrock Site to verify the Height.
Generally you require a Drop Base Carb Plate (Say a Morrosso Drop Plate) topped with a LT1 Scoop to run a 4" Air Breather in a 2nd Gen with a BBC/Holley/RPM - A 4" Breather will not clear the Hood with a BBC and Edelbrock Intake in a 2nd Gen even with a Drop Base unless you use a 3" Filter - Don't know about SBC's in a 2nd Gen - Never ran one - But a SBC over Air Gap should clear with a 3`Filter & Drop base Morrosso Plate.
There`s a Garbage Can Tin Lid in there for a Total Seal Cowl Induction:
See the Dodge Air Breather Puke Can on the PSGR Valve Cover to a Base Morrosso Carb Plate and the Dodge Heater Hose Bracket bolted to the Alternator. I`m Not Proud - Holley Annular Booster 80511-1-Edelbrock Dual Plain RPM Air Gap in Chevy Color - Almost looks Stock even with the Volvo S70 Electric Fan - LOL.
10.25:1, 7000rpm, 625Hp, Donovan Cam Gear Drive, Lunati SR 73 MKIV LS4-M21-3.31 12 Bolt Posi - 70Z
Just to show it`s a 7000rpm 460-M21 & 3.31 Gears.
Note: I just Bolt on the LT1. GM provided the Hood Sub-Frame Structure.
Believe me the Mill is not Cheap and you have to know what your doing - I`m the Mechanic & don`t trust anyone to Wrench my Ride.
She`s a 12 Sec 150+mph Road Warrior on pump gas and, over time, have owned it since 76 treating her with my personality.
Eat your heart out Baldwin & Nicky - I did it the way the General intended a 2nd Gen Z to be.
Hope my Post gives you some Idea about Cowl Induction - Be Creative - That`s GM`s Theme about 2nd Gens.