Without spending much money, you could remove the Intake port plates, and install the Exhaust port plates. The guy who did my heads told me his experience was that the Exhaust plates worked, while the intake plates don't.
After I tried that, I'd be thinking about a 650cfm Holley with vacuum secondaries - don't think you need the mechanical secondaries on a street engine. ('course, then again, you ARE talking to a guy who has FOUR carburetors on top of HIS Cleveland)
Good luck!
cobrajeff