In Richard Holdener’s “New Hemi “ book , he has a small write up about running the 4x2 Eddy manifold, with the Comp cams 273 it made more TQ and Power than the Mopar single plane under 6k rpms but the Mopar single plane did better over 6k, difference was somewhere in the 20 hp range, both fell short of the OEM EFI manifolds under 5.5k but made more top end power.
the Neighbor's 72 Cuda with a 383CI 5.7 went 10.70s with the Mopar manifold, 10.60s with the eddy 2x4 and 10.40s with the Cascar intake , Hughes pre Eagle heads , flow chart on the heads say 310@650 @ 28 depression, 2.10 Intake, 1.60 exhaust cam is a custom Comp Cams grind .590/600 255/260.