[454chevy]

Should I run a Double pumper or a vacuum secondary and what size? I am thinking 750 cfm but not sure which style DP or VS. The carb I choose will have 4 corner idle and screw in air bleeds as well. It will get tuned from idle, cruise to WOT.

Combo:
67 Camaro, street car
Big block 427
781 heads with stainless 2.19 intake and stock size 1.72 exhaust valves, mild cleanup done to ports
10:1 compression
Howards roller cam, Duration at .050" - I 229 - E 235 ---- Lift I 589" - E 601 Rpm 2000-5800
Edelbrock air gap intake
Distributor curved by FBO ignition for my combo

TH400 No stall yet but will be custom PTC unit for my combo. Guessing around 2800 stall
Rear gear is 3.50 ( 9" ) with 27.1" tire

Quick performance hasn't built the differential yet, I am considering going with 3.73 gears. Thoughts on gearing welcome as well.

 

[Ericnova72]

The combination will work with either style carb....it just comes down to personal preference or whether you want to do the necessary tuning on the VS opening rate and possible accelerator pump changes.

 

[68Chevele]

If this is a street car then run a 750 if it's a track car then an 850. VS carbs are very forgiving but from what I have seen lately some will not let the sec side open properly. You just know the DP is going to be open on the hit of the throttle.

 

[427Roscoe]

A Brawler 850 dp would be a nice carb for that combo. Imo, an 850 would make quite a bit more power and would be just as street friendly. The least expensive Brawler 850 is roughly $502 and works really well. Very easy to tune as well.

 

[Malibu ss 64]

Street? Holley 3310
Street/Strip? Holley 850 street hp or a custom carb Ive had excellent experience with Pro System.

 

[Aml383]

Should I run a Double pumper or a vacuum secondary and what size? I am thinking 750 cfm but not sure which style DP or VS. The carb I choose will have 4 corner idle and screw in air bleeds as well. It will get tuned from idle, cruise to WOT.

Combo:
67 Camaro, street car
Big block 427
781 heads with stainless 2.19 intake and stock size 1.72 exhaust valves, mild cleanup done to ports
10:1 compression
Howards roller cam, Duration at .050" - I 229 - E 235 ---- Lift I 589" - E 601 Rpm 2000-5800
Edelbrock air gap intake
Distributor curved by FBO ignition for my combo

TH400 No stall yet but will be custom PTC unit for my combo. Guessing around 2800 stall
Rear gear is 3.50 ( 9" ) with 27.1" tire

Quick performance hasn't built the differential yet, I am considering going with 3.73 gears. Thoughts on gearing welcome as well.

Theres already been some good advice given here I think but I'll add this.
With a dual plane intake you can definitely run more cfm because the cylinders dont see nearly as much as they see with a single plane .
I'd run a thousand cfm DP on that combo and they can be tuned to get allmost as good mileage as a VS carb .
On the gear ....a 350 gear and a 27 inch tire is plenty of gear running street tires I think.

You've alread got plenty of low end torque with that cam and intake . That sounds like a nice nice combo to me . I'd almost be tempted to run a single plane intake on that engine to give you more upstairs and take very little to none off the bottom.
Does your dual plane intake have a cut out in the top of the divider ?

 

[454chevy]

Yes, the divider is notched.

 

[Aml383]

Yes, the divider is notched.

Yeah that gives you more on top versus a dual plane without the cut out because it allows more air to be shared by both sides of the engine .
But again with a low end cam like that and some pretty deep gears for the steet I'd be tempted to run a single plane on that engine to grab some more power upstairs. Either way man that sounds like one hell of a nice engine set up there !
Smart . Hold the rpms lower for the street .
That thing is gonna GET IT man ! Lol
Run a big carb on it 👍

 

[Tom Mobley]

If you want to actually drive it, like put real miles on it run the 750. Get one with screw-in air bleeds. this will give a chance to tune the steady-state cruise so you can get out of the single digits gas mileage deal.

 

[GTO44]

Holley sniper

 

[Chevelle 1969]

I get 15 mpg with my pro system 1000hp with my +600hp BB on the highway. 3.55 th 400.
Just bought a Holley street hp 950 for a 600hp 454 seems like a decent carb for the price I paid. Hopefully up and running soon😃
But If Only street I think a 3310 like others suggested is hard to beat.

 

[GRC1970]

I just received a new AED carb built to my car specs 850 annular DP. I was conserned that I would struggle to get the engine to take the instant supply of the mechanical secondary but when you punch it it just takes off and goes. I still have some fine tuning to do with it but I gained a massive amount going from VS to DP on the butt dyno. It was a bit pricy but right out of the box it was really close, just a tad rich.

 

[pockets]

A Quick Fuel HR780VS or SS780VS vacuum secondary will run well, and they come with the secondary vacuum signal tube whereas 770 street avengers do not. If you drive street only, a mid 3 gear is plenty and is nicer for cruising on the highway at 70mph.
I have a AED950HO Modified and 770 street avenger with mods (secondary signal tube added, tapped main body and metering blocks for adjustable jets, secondary jet extensions and notched/winged float). I run the 770 all of the time now as I like the cold starting having a choke so I don't have to babysit it for 5 minutes until it's warm. It also is easier on the rear tires as I can slow the secondary opening to keep traction. With the double pumper as soon as the secondary squirter fuel hits and the secondaries crack the back tires break loose.

 

[Aml383]

I get 15 mpg with my pro system 1000hp with my +600hp BB on the highway. 3.55 th 400.
Just bought a Holley street hp 950 for a 600hp 454 seems like a decent carb for the price I paid. Hopefully up and running soon😃
But If Only street I think a 3310 like others suggested is hard to beat.

Nice ! That's what I call REALLY knowin how to tune em.

 

[Aml383]

I just received a new AED carb built to my car specs 850 annular DP. I was conserned that I would struggle to get the engine to take the instant supply of the mechanical secondary but when you punch it it just takes off and goes. I still have some fine tuning to do with it but I gained a massive amount going from VS to DP on the butt dyno. It was a bit pricy but right out of the box it was really close, just a tad rich.

What engine combo are you runnin that on ?

 

[Aml383]

A Quick Fuel HR780VS or SS780VS vacuum secondary will run well, and they come with the secondary vacuum signal tube whereas 770 street avengers do not. If you drive street only, a mid 3 gear is plenty and is nicer for cruising on the highway at 70mph.
I have a AED950HO Modified and 770 street avenger with mods (secondary signal tube added, tapped main body and metering blocks for adjustable jets, secondary jet extensions and notched/winged float). I run the 770 all of the time now as I like the cold starting having a choke so I don't have to babysit it for 5 minutes until it's warm. It also is easier on the rear tires as I can slow the secondary opening to keep traction. With the double pumper as soon as the secondary squirter fuel hits and the secondaries crack the back tires break loose.

Quick fuel is a nice carb . It's a brawler with a quick fuel stamp on it . The Nike sneaker with the jordan stamp.
The Jordan stamp = 30 to 40 percent more money.

 

[GRC1970]

What engine combo are you runnin that on ?

MJ 496, 781 GM heads, rpm air gap intake, isky 284/294 roller cam, th400 with 3000 stahl, 3.73 posi

 

[68Chevele]

I am glad to see someone is having good luck with QF carbs, mine all sit on the shelf.

 

[454chevy]

I just received a new AED carb built to my car specs 850 annular DP. I was conserned that I would struggle to get the engine to take the instant supply of the mechanical secondary but when you punch it it just takes off and goes. I still have some fine tuning to do with it but I gained a massive amount going from VS to DP on the butt dyno. It was a bit pricy but right out of the box it was really close, just a tad rich.

I have considered an anular discharge carb. I hear they work great on street cars.

 

[GRC1970]

I have considered an anular discharge carb. I hear they work great on street cars.

I've only got prolly 20 miles on it but I'm blown away at what it does, my car hooks pretty well on the street and for this to not bog through transition is amazing. I've had q-jets and holleys in the past and just couldn't make them work, mostly my fault not knowing well enough about carbs at the time. I also was not running near the HP as now so it was prolly just to much carb back then. I went to a vaccume secondary for 10 years and it served me well. With my new engine I was not so impressed when the secondary just didn't seem to open soon enough to get full use out of it. I am weaker working on the carb then the rest of the car so for whatever it's worth to ya I love what I have now but I'll have the 770 street avenger on the shelf just in case I need it. It got me where I was going for a long long time so I can't hate on the VS carbs either.

BTW, make sure you have enough fuel system to support whatever you decide on. These cars were equiped with adequate fuel lines for what they were built with (motor wise) mine was 5/16 all the way to the tank since it was born a 6 cylinder car so I replaced it all and went to ½ supply and ⅜ return.