I know this may not relate to your efi build but the 331 I have has a very broad powerband from 1500-6500. This is built around an Eagle 331 kit with SRP flat tops, 10.4 to 1 comp ratio with Canfield heads that were the equivalent of ARP 165 heads (1.94/1.6 valves) with 57 cc chambers. The cam is a Ford Z303 run with 1.7 rockers (.587 lift, 228* @ .050). I've never dynoed it but it makes tons of torque all though the rpm range listed with a dual plane 3x2 carb setup.