528 hemi duster

528 CRATE HEMI, 72 DUSTER STREET CAR. Runs better on one carb up to about 5k. Two eddys 600 inline on indy mod man manifold. Runs ok on both but more responsive & more power on one. Havent got into it yet been real busy so dont ask me about jetting. My 65 dart did the same thing with a 528 hemi also. So if any af you hot dogs have some good info let me know & save me some work. Carbs out of box. New build have about 25 miles on it. THANKS