650 dp vs 750 dp in a 408

I tried a 650 dp on my 408 after having a edlebrock 750 that i really did not like. What a difference it pulled much stronger. Then I put a 750 dp on because it makes sense that the 750 would be better than the 650 given the cubes. Nope the 650 absolutely out pulled the 750 dp. Both carbs are new, within the last 3 years. What gives? I have not messed with the jets or PV of either carbs. Is it simply because the smaller carb provided more torque because its smaller? Completely surprised at the difference in performance between the carbs.