The edelbrock performer intake i have is a dual plane. Also i have seen dyno results of the very same engine with a performer and air gap. The curves were almost identical but tue air gap made more peak hp.
The crank is a stock 350 crank and i do have rebuilder pistons. I run 91 or 93 octane regularly and have ran 110 leaded initially until i was comfortable with the setup. The calculators i have used showed something like 10.2:1 static and 9.67:1 dynamic.