OK guys, here's where I am with the project.
I am including "before" and "after" pics. I had a metal spinner do the tooling for a 9" flat base, out of .050" aluminum material. The pics are my prototype, so it's a little rough.
As you can see, the base is FLAT with a turned-up outside edge and 5-1/8" center hole. The next challenge was the outside edges hitting the float adjusters. I made a small round notch on each side and it dropped right on!!
It still sits on the carb lip, so it doesn't touch any parts of the carb. I don't think the air filter is compromised at all by the small notches.
I believe that this is the absolute lowest baseplate available for a 4150 carb!!
I have now been able to triple the filter area previously being used (with an x-treme top), without cutting into the hood for side clearance. It all fits under the bottom of the hood profile. If I clearance my hood scoop opening a mere 1/2" on the sides, I could go even taller!!
The .050" material could be anodized as well.
So, how much interest out there?? I have the tooling done and can pop some out if there is enough demand. I still have to figure out my costs, but I'm not trying to make a killing. I'm just glad I solved my problem!!
Any feedback, suggestions etc are most welcome.
Thanks!
Michael