For years I heard and believed that the best carb for a street driven auto
was a 750 v.s..But the two carbs I have enjoyed the most are a holley 650
d.p. and an 800 q-jet off a 77 400 trans am stick car.Contrary to popular belief
a properly sized d.p. is faster than a properly sized v.s..And nothing sounds
quite like an 800 q-jet when the secondaries open,I smile just thinking about it.
So sometimes you just have to think for yourself.

 

It depends on your definition of 'street'.
I think the arguement lies in what exactly you're after. Personally, although it's well documented that there is greater power to be had with a mechanical vs a vacuum secondary carb of the same size, I get a little tired of the poor gas mileage offered by the mechanical carb. The number one killer of economy in city driving is the accelerator pump.
As far as the Q jet goes, although they are a little more difficult to tune than a Holley, they give excellent results on the street. Although the butterflies open mechanically on a Q Jet they still fall into an ' on demand' secondary system using an air door to provide secondary side operation.
Remember that cfm requirements are dependent on cubic inch and maximum rpm. A 750 is too large for some and not large enough for others.

 

are you wanting advice to buy a carb for the street, or is this for conversation?

 

Funny thing is, a mechanical secondary and vacuum secondary carb have exactly the same accelerator pump.

In the primaries, that is. If you're getting into the secondaries of either carb, "fuel economy" is not your goal.

 

^what he said, I can't really see an accelerator pump pushing in enough fuel to make a difference in fuel economy btw, accelerator pump volume are per ten strokes of the pump so a 50cc pump really only pumps 5 cc of fuel for every complete throttle actuation. it's been proven time and time again, that fuel efficiency is all in pedal control. easy on the gas, easy on the brake will get you the best fuel economy available.

 

for the street. any properly tuned carb will work for the street. i really need to put emphasis on properly tuned. i have a hollley 600 that i haved tuned on for a while and wouldnt trade it for the world. but others will swear by others. whichever carb you get just properly tune it and it will work.

 

another good point

 

i had a motor that was capable of 10's in the 1/4 and got 18mpg on the highway.
4000 stall, no overdrive, 3.70 gear and a highly tweaked 750 DP.
just takes time and a good foot.
it would get 13mpg in town if you drove it like you didnt steal it.
ahha.