What carb do I need for SBC? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 06-26-2012, 09:34 PM
Registered User
 
Join Date: Dec 2010
Location: Elk Mound, Wi.
Posts: 52
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What carb do I need for SBC?

I have a ZZ4 350 with the GM hot cam, ported oem aluminum heads, 410 gears and 700R4 trans. Guessing 3500 curb weight. Do I run a 750 holley dp or is that too big?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-26-2012, 10:10 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 36
Posts: 795
Wiki Edits: 0

Thanks: 83
Thanked 57 Times in 47 Posts
A 600 CFM will be more than adequate. Smaller CFM carbs have smaller throats (barrels). This increases air velocity (because it is a smaller diameter) through the venturi's. This gives excellent low and mid range throttle response, power, and torque. When you start getting into higher CFM carbs, they are capable of making more power at higher RPM. But to make that additional power you must sacrifice street manners (aka low RPM power/torque where you spend 99% of street driving). With an automatic on the street you tend to keep the RPM's lower because of the shift points (another good reason to get a smaller CFM carb), with manual trans drivers tend to wind the engines higher between shifts. Everything in engine building is a balance, there is rarely a win-win design. You must find the perfect balance for you driving style and how you plan to drive this car.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-26-2012, 10:10 PM
Silver Surfer's Avatar
More machine than man
 

Last journal entry: bwaahhaahahaaahhaa
Last photo:
Join Date: Jul 2005
Location: Kansas City, MO
Age: 36
Posts: 795
Wiki Edits: 0

Thanks: 83
Thanked 57 Times in 47 Posts
And I would avoid a double pumper or mechanical secondaries for street driving. Get vacuum secondaries.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-27-2012, 09:39 AM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 30
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
personally I am not a fan of using a 600cfm carb on a modified 350. they are a perfect replacement for the typical 70's-80's stock 350s that dont like to turn more than 5000rpm. but for a modified 350 that wants to turn 6000rpm i would suggest one of these two carbs.

http://www.summitracing.com/parts/HLY-0-80783C/

or

http://www.summitracing.com/parts/HLY-0-80670/

personally i would go with the 0-80783C, 650 vacuum secondary carb. as for the double pumper idea, unless you plan on doing a good amount of racing then stay with the vacuum secondaires.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-27-2012, 01:17 PM
327NUT's Avatar
Registered User
 
Last photo:
Join Date: Dec 2004
Location: So. Utah
Age: 67
Posts: 3,202
Wiki Edits: 0

Thanks: 0
Thanked 64 Times in 58 Posts
For an all around very good, reasonably priced, easy to find carb....ya just can't beat a Holley 3310 for the street.......unless you want all the trick stuff.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-27-2012, 02:42 PM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Last photo:
Join Date: Dec 2010
Location: Portland
Posts: 1,475
Wiki Edits: 0

Thanks: 12
Thanked 222 Times in 193 Posts
The 3310 is a great carb, but unfortunately I think it's out of production. The only 3310's available are rebuilt Holleys.

I would go with the 4150 electric choke model if it's a square bore intake, or the 4175 if it's a spreadbore. 650 cfm, and vacuum sec.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-27-2012, 05:46 PM
400smb_s10's Avatar
Back Yard Junky :)
 
Last photo:
Join Date: Mar 2007
Location: Around the Corner from the middle of nowhere... Arden Ontario
Age: 28
Posts: 368
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quick question. Whats the difference of a spreadbore and a square bore? Does one make more power and torque through out the RPM range?
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-27-2012, 05:55 PM
spinn's Avatar
Fought beside and with you 92'
 

Last journal entry: This makes a huge difference
Last photo:
Join Date: Oct 2004
Location: midwest
Posts: 2,382
Wiki Edits: 0

Thanks: 11
Thanked 78 Times in 76 Posts
What is with the holleys. How about the AVS/AFB style. They would be my first choice for anything on the street. The Holley is just a jet hole , there isnt much to the metering system except for wide open tuning.

Square has 4 same sized throttle blades. The spread has small primaries to drive on and large secondaries for power.

This is pretty dead on.
-Carburetors are rated by CFM (cubic feet per minute) capacity. 4V carburetors are rated at 1.5 inches (Hg) of pressure drop (manifold vacuum) and 2V carburetors at 3 inches (Hg). Rule: For maximum performance, select a carburetor that is rated higher than the engine CFM requirement. Use 110% to 130% higher on single-plane manifolds. Example: If the engine needs 590 CFM, select a carburetor rated in the range of 650 to 770 CFM for a single-plane manifold. A 750 would be right. An 850 probably would cause driveability problems at lower RPM. A 1050 probably would cause actual loss of HP below 4500 RPM. For dual-plane manifolds use 120% to 150% higher

Last edited by spinn; 06-27-2012 at 06:02 PM.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 06-27-2012, 05:58 PM
400smb_s10's Avatar
Back Yard Junky :)
 
Last photo:
Join Date: Mar 2007
Location: Around the Corner from the middle of nowhere... Arden Ontario
Age: 28
Posts: 368
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
ok thanks for the input
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 06-27-2012, 06:08 PM
Registered User
 
Join Date: Dec 2010
Location: Elk Mound, Wi.
Posts: 52
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If I understand these replies I should use like the avenger 670cfm on my dual plane manifold? Thanks
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 06-27-2012, 06:09 PM
spinn's Avatar
Fought beside and with you 92'
 

Last journal entry: This makes a huge difference
Last photo:
Join Date: Oct 2004
Location: midwest
Posts: 2,382
Wiki Edits: 0

Thanks: 11
Thanked 78 Times in 76 Posts
Look at the tech discussion at edelbrock dot com . It is a quick read. Check out the cfm requirement and 5 basic levels of engine build requirements.

It is no lies or superstition.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 06-28-2012, 07:55 PM
1971BB427's Avatar
Registered User
 

Last journal entry: Latest changes
Last photo:
Join Date: Dec 2010
Location: Portland
Posts: 1,475
Wiki Edits: 0

Thanks: 12
Thanked 222 Times in 193 Posts
Quote:
Originally Posted by spinn View Post
What is with the holleys. How about the AVS/AFB style. They would be my first choice for anything on the street.
My first choice for street or strip has and always will be a Holley. No problem if you like Eddys, but I've had nothing but headaches with the couple I've owned.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 06-28-2012, 11:39 PM
spinn's Avatar
Fought beside and with you 92'
 

Last journal entry: This makes a huge difference
Last photo:
Join Date: Oct 2004
Location: midwest
Posts: 2,382
Wiki Edits: 0

Thanks: 11
Thanked 78 Times in 76 Posts
Cool, but do you have anything to say that makes them your first choice?

The transition and part throttle calibrations are far superior on the road. Hollies have 3 hole steps in the plates. The smaller volume bowls arent going dry unless you really are up over 5500rpms . Cant leak fuel , unlike the holley where the gaskets seals the fuel. Rod metering and jets are a snap. No crazy power valve that is either 6.5 rating or wrong. All it is are holes. AFB/AVS/Qjet has a rod in the fuel jet hole helps that maintain velocity at all rpms. The spring and balance system keeps the side to side evened out. No powervalve boost indexing needed for superchargers.

Just a few things to think about if you drive your car.

Usually people like the first carb they learned on. Also holleys were rumored to be on all the 80's drag cars so they had to be better,. Superstition. They were replacing qjets with them constantly in the 80's. A Qjet is a fine carb and could never figure that downgrade out.

Bad mood, maybe. Please tell me some ways that holley is better under 5000 rpm. I am sorry to have brought this up, but am curious what others think.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 06-29-2012, 08:13 PM
my87Z's Avatar
Veteran/Firefighter-EMT-I CRT
 
Join Date: Mar 2009
Location: maryland
Age: 30
Posts: 1,685
Wiki Edits: 0

Thanks: 6
Thanked 11 Times in 11 Posts
I to would choose the holley first, I don't have bunch of technical data to back up why, only my experiences with edelbrocks. I have attempted to use 2 edelbrock carbs, one as a replacement for a Q-jet, and one on my very first engine build while in high school. I had problems with both. I ended up rebuilding the Q-jet and on the other motor I put a 3310 Holley 750 which required very little work to get tuned right. For a street motor I don't have anything wrong with a Q-jet except that once they need to be rebuilt they never seem to be the same anymore. It could just be me. I've rebuilt numerous holley's and never had any problems with them. I will admit that I have never used one of the newer edelbrock carbs.

When it comes right down to it, I'm just not a fan of edelbrock products besides their intakes.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 06-29-2012, 08:25 PM
BigChevyFTW
Guest
 
Quote:
Originally Posted by wibas View Post
If I understand these replies I should use like the avenger 670cfm on my dual plane manifold? Thanks
that is more for a 383ci motor. For a 350, depending on the duration of the cam. id go 600cfm all day unless its a beefy cam. then, a 650 would be the highest i would go! if its a stick car dont worry go 670cfm but silver surfer is right on the money to the TTTTTTTTTTTT!!!!!!!!
Reply With Quote Quick reply to this message
The Following User Says Thank You to For This Useful Post:
Silver Surfer (06-29-2012)

Tags
350, carburetor recommendation

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
SBC, what carb? 73nova350 Engine 12 01-27-2012 04:00 PM
SBC Backfire through carb Jay Gadsby Engine 23 06-17-2011 02:58 PM
Right carb for my sbc rebuild? chevymudd54 Engine 10 04-22-2010 07:05 PM
sbc carb. spacer hottrodz Engine 3 12-13-2006 10:39 AM
what carb for sbc 400 camino_man Engine 6 09-18-2005 04:48 PM


All times are GMT -6. The time now is 02:30 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.