Been trying to post on this forum for ages, just figured out my password
Thanks for the ton of effort you put into this testing and sharing the data
Anyway If you plan on retesting your 3D printed manifold I have another manifold you can try, It's a factory D1ZX-FA manifold with a 4150/4160 carb flange.(no Idea why ford made it but it's factory ....)
Also have a D1ZX-DA (dual plane 4150 flange) , and a Bud Moore box with a factory dominator top
All the Bud Moore maxi plenums I've seen have that divider added under the top. since these are so terrible with a carb, I wonder if it's worth doing an EFI conversion on one ....
Let me know if you want to borrow any of these ...
John