[Goat Blower]

Pull your plugs and see if they're all sooty black. It looks and sounds like you have way too much injector to compensate for with a SAFC. I just had the exact same symptoms putting in 1600's. It would idle but fall on it's face with any boost. Each time I took out 10% from the fuel tables it would run a little better until it just flies. A wideband makes easy work of this stuff, but you can still oldskool it by reading the plugs.