vacuum secondary vs. double pumper?

back to back test on my 69 barracuda....the 750 dp is a good tenth qucker then the 750 vacuum secondary ....both carbs have billet bases..proform main bodies...billet metering blocks...and the vacuum secondary carb uses a quick fuel adjustable pod ...

leaving on a trannybrake with throttle on the floor and two step at 3000 rpm...