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...

X2 except no trans brake both stock Holleys but the VS had a lot of track time with various springs and was well sorted. My car picked up 2 mph and .2 in the quarter.