What Size Carb?
Thread Starter
Intermediate
Joined: Nov 2006
Posts: 47
Likes: 0
From: Orlando Florida
What Size Carb?
ive been talking with friends about which carb to get... what size which brand im looking for about 525 horsepower with the edelbrock high compression heads... i have a 74 with a 454... ive been told a 750 holley double pumper?? and another friend told me for this set up and having a big block i shouldnt use under 900cfm carb??? he said at the top end my car will be starving for fuel... but none of us have delt with carbs much we have all built up fuel injection cars... so i need some help
Racer
Joined: May 2005
Posts: 470
Likes: 1
From: Amelia Ohio
Holley's web site has a guide for picking a carb, but I would say bigger than a 750 depending on how much you plan to spin. No matter what the cfm you'll still have to jet and adjust to the motor.
Chris
Chris
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
Multiply 454 x the max RPMs you will turn, and divide this number by 3456. Then multiply that number by your projected volumetric efficiency (VE). VE is usually about .75 to .80 for a stock engine, .80-.85 for a high performance engine. A full race engine can have .9 to .95, possibly even 1.0 with supercharger. This will give you the proper size for your carb. God bless, Sensei
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
Originally Posted by 74vette454
ive been talking with friends about which carb to get... what size which brand im looking for about 525 horsepower with the edelbrock high compression heads... i have a 74 with a 454... ive been told a 750 holley double pumper?? and another friend told me for this set up and having a big block i shouldnt use under 900cfm carb??? he said at the top end my car will be starving for fuel... but none of us have delt with carbs much we have all built up fuel injection cars... so i need some help
The CFM rating of a carburetor has nothing to do with the fuel/air mixture that that carburetor can provide.
Whatever carburetor you put on this engine is going to need tuning. You can't just change a few numbers in a computer either. You're going to have to take it apart (several times) and change jets and springs and rods and all that sort of thing.
What kind of carburetor do you want to put on it? Whatever it is I suggest you go get some books on it.
BigBlockk
Later.....
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
Originally Posted by evalu8r
Holley's web site has a guide for picking a carb, but I would say bigger than a 750 depending on how much you plan to spin. No matter what the cfm you'll still have to jet and adjust to the motor.
Chris
Chris
www.holley.com has a carb finder. You just answer a series of questions and it suggests several carbs.
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
i installed an edelbrock 750 cfm carb on my 350 when i put a heavy cam and performer manifold on it as well. of course i also have intentions of turbocharging in the future. i still need to fine tune mine, but when it was pre-calibrated from the company it was indeed running a bit too lean.
Safety Car
Joined: Dec 2004
Posts: 4,876
Likes: 1
From: Jersey Shore Exit 98
Originally Posted by 74vette454
ive been talking with friends about which carb to get... what size which brand im looking for about 525 horsepower with the edelbrock high compression heads... i have a 74 with a 454... ive been told a 750 holley double pumper?? and another friend told me for this set up and having a big block i shouldnt use under 900cfm carb??? he said at the top end my car will be starving for fuel... but none of us have delt with carbs much we have all built up fuel injection cars... so i need some help
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Melting Slicks
Joined: Nov 2003
Posts: 2,362
Likes: 1
From: San Antonio TX
Originally Posted by 74vette454
ive been talking with friends about which carb to get... what size which brand im looking for about 525 horsepower with the edelbrock high compression heads... i have a 74 with a 454... ive been told a 750 holley double pumper?? and another friend told me for this set up and having a big block i shouldnt use under 900cfm carb??? he said at the top end my car will be starving for fuel... but none of us have delt with carbs much we have all built up fuel injection cars... so i need some help
750 vac sec if you have an auto with stock gearing would be a good all around carb.
850 dp with a standard or even an auto if you have a loose torque converter and some gears to go along with it.
There are many things to consider when choosing a carb for a car.
I myself am going to use a 850 DP Holley on a 468 CI with a 3000 stahl converter and a Turbo 400 with a street strip kit in it and 3.73 rear gear. I would go to a larger carb but I do not see myself turning the Big Block 6500 all of the time. The cam is 255/263 at .050, .626"/.626" Lift solid flat tappet. Heads are Chev Iron Oval port with some clean up work done with 2.19IN 1.88Ex with 10 to 1 compression.
