At the bottom of this page there is an explanation on how to measure Carb pad height. You can measure both and see how much difference there is.
http://www.edelbrock.com/automotive/mc/manifolds/
For the Air Gap:
Manifold height: A-4.48", B-5.56; Carb pad height:
5.02".
I don't have the stock one to give you that measurement. Maybe another member has one that can get you the measurement. It should clear the hood unless possibly on Ram Air installations.
Edit:
I just added Ram Air to my car using a Blue Thunder manifold and the Carb Pad Height is 4.90". I am just at the limits, anymore taller and I would have had hood clearance issues.
I LOVE that air gap intake....i just bought a 1971 H code, and I THINK the above answers my question, which is: 1) will a standard factory air cleaner clear and air gap manifold clear factory Mach 1 ducted hood? If it WILL clear a Ram Air set up, it definitely should clear my NON ram air assembly. Also, I installed a Blue Thunder on another Mach 1 M code. It cleared, but it was close. 4.90" is the carb pad height as noted above for the Blue Thunder. The Edelbrock Air Gap is 5.02", so I will be .12" taller. Not much more, but like I said, on my M code Install with factory non ram air cleaner it was CLOSE. After reading the above that someone cleared a ram air set up with a Blue Thunder, I do believe the additional room required by the Ram Air set-up exceeds .12". Thanks for the help! If anyone knows that is not the case, please let me know! That is tight enough, that even carb type might make a difference. I used a 4v Holley on my M code Blue Thunder application, and will probably do so again here with my H code. I am reasonably sure the weight savings alone make me feel a little better. I am guessing close to 20 pounds difference? Thanks again.
