C9x Imo double pumpers are for the track, but there are guys out there who know what they're doing and run them on the street with a high degree of success.
As witnessed by a couple of posters above.

That said, I prefer vacuum secondary or air valve secondary carbs on the street.
Makes for a crisp running engine that launches well with mild cam or a fairly big cam.

The dual quad setup I was running on my 2400# 32 roadster utilized straight, non-progressive linkage to the 500 cfm Carters.
The 462" Buick engine responded well with the smaller carbs and tip-in on the secondaries was very smooth.
Kenne-Bell recommended dual 750's, but I elected to go with the 500's because my goal was to have an engine that responded well in the low and mid-range.

If I was building a drag race bracket type car I'd still run vacuum or air valve secondaries.
They are trouble free for the most part and since bracket cars don't need that last little bit of horsepower you can give up some and pay attention to driving the car rather than dinking around with it in the pits.
Kind of a change the oil and go racing car.

I pulled the dual quads and big cam to use in an upcoming project.
An Edelbrock Performer intake and 750 cfm Carter went on the engine along with a milder cam.
The engine responds well and mileage in town runs 10-12 mpg.
Highway runs about 16 mpg.
If . . . you keep your foot out of it.
The carb is jetted/rodded for the 3300' altitude I live at now and it still runs good when we go down the hill to the river at about 450' altitude.

Mileage could be better I suppose, but the 32 has the aerodynamic qualities of a brick.
Fun quotient is pretty high though....

Get yourself a street oriented carb for the car.
Amen, I agree completly. I have changed from a mech. secondary to a vacuum carb, several times...maybe 6 or 8, on small blocks and big blocks....and in EVERY case, it was more responsive, and overall, just ran much better. I know guys myself who are running double pumpers on the street, and they seem to run good...but then again, Im not the one riding in the car, or cold starting it. I'll stick with what I know works for me. Im sure you wont be sorry with a good vacuum secondary carb. John