choosing the right carb
Heel & Toe
Joined: Feb 2015
Posts: 21
Likes: 4
Oh boy!!
That aside I agree with some other comments here that you should evaluate what you get don't be real eager to replace it. I know tinkering with it is what's fun.. well tinkering with what it's got could be a start as generally the mfg carb set up was probably pretty good for that engine. Now the stock 69 bb came with a 750 cm qjet I believe and I'm a lover of qjets. Properly set up and working qjet will perform as well as anything you'll put on it and won't waste fuel. But they do take a lot of study time to understand them but not that much more than your Holley,Quickfuels etc. If you want to try a Holley style, I see no reason why a vacuum secondary system can't be dialed in and lot less work dialing it in vs a mechanical. If somebody isn't running a high rpm race engine I don't recommend over 750 or manual secondaries. It's not necessary, waste fuel, and more work to dial in. But have fun with whatever you choose. Might find once you get the car money might be better spent elsewhere or it has bigger priorities.
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 34
Likes: 0
Congrats. You know that saying opinions are like ***holes. Well opinions are carburetors are not because everybody has two or three That aside I agree with some other comments here that you should evaluate what you get don't be real eager to replace it. I know tinkering with it is what's fun.. well tinkering with what it's got could be a start as generally the mfg carb set up was probably pretty good for that engine. Now the stock 69 bb came with a 750 cm qjet I believe and I'm a lover of qjets. Properly set up and working qjet will perform as well as anything you'll put on it and won't waste fuel. But they do take a lot of study time to understand them but not that much more than your Holley,Quickfuels etc. If you want to try a Holley style, I see no reason why a vacuum secondary system can't be dialed in and lot less work dialing it in vs a mechanical. If somebody isn't running a high rpm race engine I don't recommend over 750 or manual secondaries. It's not necessary, waste fuel, and more work to dial in. But have fun with whatever you choose. Might find once you get the car money might be better spent elsewhere or it has bigger priorities.
That aside I agree with some other comments here that you should evaluate what you get don't be real eager to replace it. I know tinkering with it is what's fun.. well tinkering with what it's got could be a start as generally the mfg carb set up was probably pretty good for that engine. Now the stock 69 bb came with a 750 cm qjet I believe and I'm a lover of qjets. Properly set up and working qjet will perform as well as anything you'll put on it and won't waste fuel. But they do take a lot of study time to understand them but not that much more than your Holley,Quickfuels etc. If you want to try a Holley style, I see no reason why a vacuum secondary system can't be dialed in and lot less work dialing it in vs a mechanical. If somebody isn't running a high rpm race engine I don't recommend over 750 or manual secondaries. It's not necessary, waste fuel, and more work to dial in. But have fun with whatever you choose. Might find once you get the car money might be better spent elsewhere or it has bigger priorities.
you know it man , can never get tiered of "tinkering" haha
i'm not planning high RPM that's true. But if the double pumper would work fine I see no problem with getting it.
the car arrives tomorrow and I'll see what happens then
He could probably get away with a vacuum secondary on it esp with those gears;(not sure Id call the car light)plenty of performance cars came with vac secondarys back then.... Personally I like a double pumper on stick cars...actually most hot rods period. Personal choice
toobroketoretire just cant catch a break...he says DP you guys tear him up, VS same thing. Wow
toobroketoretire just cant catch a break...he says DP you guys tear him up, VS same thing. Wow
even though there is this guy who told me the that with the gears ratio that i have on the 4 speed , vac secondary is recommended.
ratio is 3.08
3310 is an excellent choice.....best bang for the buck out there...
But as others have said....why do you need a new one?
And as far as annular boosters go....one only sees big gains on a low vacuum motor with bad signal.....
Holley will not recommend a Vac Sec for a stick....but it still works very well if the secondary spring is lightened up to account for the fast increase in RPM under a load in first gear.
I have heard a LOT of good things about Quick Fuel....but have never tried one.....they are kinda pricy...but all tuner carbs are.
If cost is no object....go with Patrick at Pro Systems.....
This is my opinion...based on years of screwing around...and your results may vary!
Jebby
But as others have said....why do you need a new one?
And as far as annular boosters go....one only sees big gains on a low vacuum motor with bad signal.....
Holley will not recommend a Vac Sec for a stick....but it still works very well if the secondary spring is lightened up to account for the fast increase in RPM under a load in first gear.
I have heard a LOT of good things about Quick Fuel....but have never tried one.....they are kinda pricy...but all tuner carbs are.
If cost is no object....go with Patrick at Pro Systems.....
This is my opinion...based on years of screwing around...and your results may vary!
Jebby
thanks man thats why i post this thread to get more infos and decide what i should get
btw screwing around gives you a good experience.. sometimes you f*** things up but at least we will learn haha
I too have been guilty of making a reply to quickly after not fully reading what the poster actually said, I am far more careful that that and do rear all posts...
So when you get past the cats telling you keep what you have and etc
The main thing you need is a bit more info as in which heads you have will make a difference, oval port or rectangle port, very different creatures made for different RPM power bands.
As far as pulling the old carb just to save it I would have to say that in and of itself is a waste of $$$ you are modding the car anyway having the old carb in a box will only soothe a purist would be buyer so much.
So when you get past the cats telling you keep what you have and etc
The main thing you need is a bit more info as in which heads you have will make a difference, oval port or rectangle port, very different creatures made for different RPM power bands.
As far as pulling the old carb just to save it I would have to say that in and of itself is a waste of $$$ you are modding the car anyway having the old carb in a box will only soothe a purist would be buyer so much.
i don't like it haha
for the money , i bought the car for a good price less than what was in my mind , so i kinda have money that i thought it was going to be spend on buying the car
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
If youre set on getting the holley dp try and find one similar to the hp series that had adjustable IAB etc in the top. If it gets cammed up that can solve the stinky idle syndrome.
holleyperformance on ebay sells returns/blems super cheap just picked up 2 intakes last week from them that woulda run me over $700 at Summit, spent less than $350
holleyperformance on ebay sells returns/blems super cheap just picked up 2 intakes last week from them that woulda run me over $700 at Summit, spent less than $350
Last edited by cv67; Nov 19, 2015 at 07:57 AM.
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 34
Likes: 0
If youre set on getting the holley dp try and find one similar to the hp series that had adjustable IAB etc in the top. If it gets cammed up that can solve the stinky idle syndrome.
holleyperformance on ebay sells returns/blems super cheap just picked up 2 intakes last week from them that woulda run me over $700 at Summit, spent less than $350
holleyperformance on ebay sells returns/blems super cheap just picked up 2 intakes last week from them that woulda run me over $700 at Summit, spent less than $350
thank you for reminding me of that
750 CFM ULTRA DOUBLE PUMPER CARBURETOR
Electric Choke Mechanical Secondaries
PART# 0-76750BL
i think i'm getting this one
now for the Intake manifold
should i go with the single plane or dual plane
my buddy told me to go with the dual plane for a street car.
any opinions on that?
https://www.holley.com/products/inta...lds/parts/8019
i was looking at this one
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
yes i found one that has those idle air bleed on top
thank you for reminding me of that
750 CFM ULTRA DOUBLE PUMPER CARBURETOR
Electric Choke Mechanical Secondaries
PART# 0-76750BL
i think i'm getting this one
now for the Intake manifold
should i go with the single plane or dual plane
my buddy told me to go with the dual plane for a street car.
any opinions on that?
https://www.holley.com/products/inta...lds/parts/8019
i was looking at this one
thank you for reminding me of that
750 CFM ULTRA DOUBLE PUMPER CARBURETOR
Electric Choke Mechanical Secondaries
PART# 0-76750BL
i think i'm getting this one
now for the Intake manifold
should i go with the single plane or dual plane
my buddy told me to go with the dual plane for a street car.
any opinions on that?
https://www.holley.com/products/inta...lds/parts/8019
i was looking at this one
Performer RPM is a second choice.....
Jebby
Safety Car
Joined: Jan 2009
Posts: 3,736
Likes: 56
From: anchorage ak
Holley ultra 950 hp double pumper flows 830 cfm. Oh and as cuisenartvette said the corvette is not a light as far as sports cars go.
Last edited by bluedawg; Nov 20, 2015 at 01:15 AM.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
IMCO a 750 VS belongs on a mild 350 SBC auto. I personally wouldn't put anything smaller than an 830 DP on a stout BBC 4-speed C3, as I've successfully run as large as 1050 Dom (progressive 2nds) on a moderate street 427. YMMV
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Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
:rof l:
Formula for carburetor/throttle-body CFM:
Cubic inch of motor multiplied by max RPM, divided by 3454
454 X 6500?? /3453= 855cfm
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I personally have a Demon 825 cfm that has been professionally bench flowed and then tested on dyno test mule motor of @ equal HP.
I believe in chokeless double pumpers with bowl sight glasses and 4 corner A/F ratio adjusters on a intake manifold that matches the head port size. Single planes require less cfm than a dual plane intake. I think that the Holley hp series come close out of the box as do quick fuel and proform carbs.......
Everything you said about the motor tends to say that it is just a low budget rebiuld. 427 heads mean nothing because they made low powered 427's that came in family station wagons and the 390 hp vette. 10/10 crank indicates that it has a crappy cast crank that was blemished from ware requiring machining. Smart people throw them away and install an internally balanced forged crank. 9.75 C/R is fluff for just some cheap cast piston with stock rods.
I believe in chokeless double pumpers with bowl sight glasses and 4 corner A/F ratio adjusters on a intake manifold that matches the head port size. Single planes require less cfm than a dual plane intake. I think that the Holley hp series come close out of the box as do quick fuel and proform carbs.......
Everything you said about the motor tends to say that it is just a low budget rebiuld. 427 heads mean nothing because they made low powered 427's that came in family station wagons and the 390 hp vette. 10/10 crank indicates that it has a crappy cast crank that was blemished from ware requiring machining. Smart people throw them away and install an internally balanced forged crank. 9.75 C/R is fluff for just some cheap cast piston with stock rods.
Race Director
Joined: May 2003
Posts: 10,956
Likes: 409
From: California
I personally have a Demon 825 cfm that has been professionally bench flowed and then tested on dyno test mule motor of @ equal HP.
I believe in chokeless double pumpers with bowl sight glasses and 4 corner A/F ratio adjusters on a intake manifold that matches the head port size. Single planes require less cfm than a dual plane intake. I think that the Holley hp series come close out of the box as do quick fuel and proform carbs.......
Everything you said about the motor tends to say that it is just a low budget rebiuld. 427 heads mean nothing because they made low powered 427's that came in family station wagons and the 390 hp vette. 10/10 crank indicates that it has a crappy cast crank that was blemished from ware requiring machining. Smart people throw them away and install an internally balanced forged crank. 9.75 C/R is fluff for just some cheap cast piston with stock rods.
I believe in chokeless double pumpers with bowl sight glasses and 4 corner A/F ratio adjusters on a intake manifold that matches the head port size. Single planes require less cfm than a dual plane intake. I think that the Holley hp series come close out of the box as do quick fuel and proform carbs.......
Everything you said about the motor tends to say that it is just a low budget rebiuld. 427 heads mean nothing because they made low powered 427's that came in family station wagons and the 390 hp vette. 10/10 crank indicates that it has a crappy cast crank that was blemished from ware requiring machining. Smart people throw them away and install an internally balanced forged crank. 9.75 C/R is fluff for just some cheap cast piston with stock rods.
I think George here has it nailed down! this^^^^^
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Like it or not mechanical secondary carburetors and short-runner single plane intake manifolds are intended for track racing where engine speeds remain high. Which is why none of the "big three" American automobile manufacturers ever used them. Its torque that gets a car in motion and its torque that keeps it in motion and its the weekend warriors who are determined to kill that torque in any way they can.
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 34
Likes: 0
Thank you everybody for all the information you provide
So i made my mind i'm going with the double pumper and dual plane intake
WEIAND STEALTH INTAKE - CHEVY BIG BLOCK V8
PART# 8019
https://www.holley.com/products/inta...lds/parts/8019
750 ULTRA DOUBLE PUMPER
Electric Choke
PART# 0-76750BL
https://www.holley.com/products/fuel...arts/0-76750BL
again thanks , a lot of good infos in here
So i made my mind i'm going with the double pumper and dual plane intake
WEIAND STEALTH INTAKE - CHEVY BIG BLOCK V8
PART# 8019
https://www.holley.com/products/inta...lds/parts/8019
750 ULTRA DOUBLE PUMPER
Electric Choke
PART# 0-76750BL
https://www.holley.com/products/fuel...arts/0-76750BL
again thanks , a lot of good infos in here
Drifting
Joined: Aug 2009
Posts: 1,346
Likes: 160
From: new iberia la
Race Director
Joined: Dec 1999
Posts: 11,096
Likes: 990
From: Sierra Foothills CA
Thank you everybody for all the information you provide
So i made my mind i'm going with the double pumper and dual plane intake
WEIAND STEALTH INTAKE - CHEVY BIG BLOCK V8
PART# 8019
https://www.holley.com/products/inta...lds/parts/8019
750 ULTRA DOUBLE PUMPER
Electric Choke
PART# 0-76750BL
https://www.holley.com/products/fuel...arts/0-76750BL
again thanks , a lot of good infos in here
So i made my mind i'm going with the double pumper and dual plane intake
WEIAND STEALTH INTAKE - CHEVY BIG BLOCK V8
PART# 8019
https://www.holley.com/products/inta...lds/parts/8019
750 ULTRA DOUBLE PUMPER
Electric Choke
PART# 0-76750BL
https://www.holley.com/products/fuel...arts/0-76750BL
again thanks , a lot of good infos in here
I really like the quality of their carbs and rebuild kits. After seeing the quality of the gaskets on a friend's Quickfuel carb I now only use their rebuild kits.
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
When you finally realize you bought the wrong style of carburetor Holley will be more than happy to sell you the right style for another $550 (plus shipping). Its your money so you can waste it in any way you wish.