what cfm to use on 350 chevy - 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 12-02-2011, 01:51 PM
1996thunderchicken's Avatar
ALL AMERICAN MADE
 
Last photo:
Join Date: May 2011
Location: il
Age: 28
Posts: 128
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
what cfm to use on 350 chevy

Up date on my situation come to find out the guy was wrong on the carb he put on it it was a 600 cfm edelbrock performer i was wanting to know if i should go higher than a 650 i been looking on the web and found a company that rebuilds carbs and sells that them at a pretty nice price cause with my edelbrock im gonna have to do more than rebuild but im just trying to figure out what cfm i should go for on aftermarket carbs and the website i was checking out is www.carburetorsandmore.com if any one wants to check it out but back to my question is that i really need to get a carb fast

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 12-02-2011, 02:24 PM
Custom10's Avatar
my KARMA ran over my DOGMA
 

Last journal entry: SS
Last photo:
Join Date: May 2009
Location: Saskatchewan, Canada
Age: 50
Posts: 1,101
Wiki Edits: 0

Thanks: 18
Thanked 31 Times in 27 Posts
There are a couple things that you need to consider, 1 cubic inches of motor and 2 the maximum RPM the motor will turn. Also a performance engine will require a bit more than a stock motor of the same cubic inch and rpm limit

Post what ya got
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 12-02-2011, 02:41 PM
1996thunderchicken's Avatar
ALL AMERICAN MADE
 
Last photo:
Join Date: May 2011
Location: il
Age: 28
Posts: 128
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
it is a jasper performance 350 when i got the car it had headers and the 600 cfm edelbrock on it but when using the edelbrock it would act as if it where starving it self on the upper rpms the engine it self like i said was a 350 4bolt main and its in my 1977 chevrolet nova it is backed by a mildly built th350 tranny im just wandering if im under carbing it and i know i dont want to over carb it had built a holley but didnt know that the body was cracked what luck lol
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 12-02-2011, 03:27 PM
Registered User
 
Last photo:
Join Date: Jun 2010
Location: Syracuse, NY
Posts: 2,334
Wiki Edits: 0

Thanks: 659
Thanked 249 Times in 222 Posts
Most people overcarb an engine. realistically I doubt your engine would ever need the extra 50cfm. Unless you're trying to wind this thing to 5 grand and rip some pavement loose. For general every day driving, a 600 is fine.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 12-02-2011, 03:37 PM
1996thunderchicken's Avatar
ALL AMERICAN MADE
 
Last photo:
Join Date: May 2011
Location: il
Age: 28
Posts: 128
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I do want to rip some pavement up id like that alot but if I did go the 50 extra cfm I wouldnt hurt anything would i
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 12-02-2011, 04:03 PM
NovaJoe1973's Avatar
Registered User
 
Last photo:
Join Date: Nov 2011
Location: WA state
Posts: 20
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What is the rpm range of the engine? I had an rv cam in my 355 with a holley 600 and pulled to 5700 no problem.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 12-02-2011, 08:30 PM
lakeroadster's Avatar
Hot Rods are Built, not Bought
 

Last journal entry: Lakeroadster's '31 Model A Tudor
Last photo:
Join Date: Dec 2001
Location: High Plains - Rocky Mountains
Age: 53
Posts: 695
Wiki Edits: 0

Thanks: 38
Thanked 106 Times in 96 Posts
Quote:
Originally Posted by 1996thunderchicken
I do want to rip some pavement up id like that alot but if I did go the 50 extra cfm I wouldnt hurt anything would i
Yes, it will hurt something. The 600 is more than enough carb for a street driven 350 that has mild compresssion.

To big of a carb. hurts driveability. If you want crisp throttle response, go with the 600 cfm. While it may be cool to say you have a 750 carb, it is overkill unless your motor is a high rpm balanced and blueprinted, high compression motor.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 12-02-2011, 09:48 PM
kleen56's Avatar
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Santa Clarita CA
Posts: 802
Wiki Edits: 0

Thanks: 4
Thanked 6 Times in 6 Posts
I understand what your saying about the Edelbrock carb feeling like it was starving for fuel. I ran the 600 cfm on my 351 Windsor engine and the performance was really poor. The Edelbrock was reliable and fairly easy to work on, but when you put the pedal down. Not much happened. I'm pretty much a Holley person anyways, so I switched the 600 Edelbrock with a Holley 650 DP. I did have to jet it down a step and do some adjustments but the engine came alive. I like the Double pumpers because when you step down on the pedal, the secondaries will open. I don't want this post to become a debate about Edelbrock vs. Holley because there's plenty of posts in here. I'm just saying what my experience is.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 12-02-2011, 11:16 PM
1996thunderchicken's Avatar
ALL AMERICAN MADE
 
Last photo:
Join Date: May 2011
Location: il
Age: 28
Posts: 128
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
yea i know not to go for a 750 i was wandering about a 650 or a 625 carter afb carb i know same concept as a edelbrock now i might look into holley 650 vac secondairies but i know what every one is say about driveabilty and yes in my current posisstion meaning my wifes van broke tonight lol lovely right not sure what happened was coming off the highway and it started jerking then would quit then it would happen again and it kept up untill we got about 15 miles from home and it just crapped out im hoping just a cam sensor but probably more than that my luck
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 12-02-2011, 11:45 PM
kleen56's Avatar
Registered User
 
Last photo:
Join Date: Oct 2006
Location: Santa Clarita CA
Posts: 802
Wiki Edits: 0

Thanks: 4
Thanked 6 Times in 6 Posts
Sorry to hear that with the wife's car! Here is another thought. I have a lot of friends who swear by the quadrijet carbs. There pretty easy to find and cheap enough on the pocket.. They are great carbs as well. Most people freak out on rebuilding them, but their pretty simple once you've done it.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 12-03-2011, 08:43 AM
lakeroadster's Avatar
Hot Rods are Built, not Bought
 

Last journal entry: Lakeroadster's '31 Model A Tudor
Last photo:
Join Date: Dec 2001
Location: High Plains - Rocky Mountains
Age: 53
Posts: 695
Wiki Edits: 0

Thanks: 38
Thanked 106 Times in 96 Posts
I too like Holley double pumpers. I have a vacuum secondary 600 double pumper on my Model A (350 sbc) and a manual secondary 600 double pumper on my Model T (5.O HO sbf) and both are great carb's.

My 65 C10 (350 sbc) has an Edelbrock 600 cfm carb., was on it when I bought it. It runs nice too.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 12-03-2011, 10:56 AM
adantessr's Avatar
'23 T-Bucket Pickup
 
Last wiki edit: Troubleshooting ignition Last photo:
Join Date: Jun 2010
Location: South Charleston , WV
Age: 62
Posts: 1,549
Wiki Edits: 3

Thanks: 43
Thanked 17 Times in 15 Posts
The main thing with any carb, no matter what brand you are using, is proper jetting for the engine that it is installed on. I suspect that if your edelbrock is starving your engine, it is not for lack of airflow, it just needs a little bit bigger jets. Inversely my 800 cfm quadrajet on my totally stock 305 needed larger secondary meteriing rods to get rid of a high rpm exhaust backfire caused by overfueling above 4000 rpm. Yeah, I know you're thinking. "What ? 800 cfm on a 305 ?" A q-jet won't give any more airflow (cfm) than what the engine can use.
BTW . I was checking awhile back about min cfm needed for a 400 hp 454 @ 4500 rpm. The site that I was looking at said that 560 crm was plenty. So your edelbrock should do what you need, once you get it jetted correctly.
Attached Thumbnails
Click image for larger version

Name:	'91 305 engine.jpg
Views:	110
Size:	1,017.6 KB
ID:	60469  
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 12-03-2011, 12:21 PM
cobalt327's Avatar
WFO
 
Last wiki edit: Intake manifold
Last journal entry: 1980 Malibu Wagon
Last photo:
Join Date: Mar 2009
Location: Atlanta
Age: 60
Posts: 5,037
Wiki Edits: 1616

Thanks: 128
Thanked 597 Times in 546 Posts
Quote:
Originally Posted by 1996thunderchicken
I do want to rip some pavement up id like that alot but if I did go the 50 extra cfm I wouldnt hurt anything would i
One problem w/the plain vanilla Edelbrock Performer 600 cfm carb is the lack of adjustability of the secondaries. They solved the problem w/the 650 cfm AVS Thunder series of carbs, and that is what I would recommend unless you were to use a Holley 600 cfm like the 1850. A healthy SBC 350 will not have a problem using the AVS 650.

Sometimes guys mistake a dual feed for a double pumper. There's no DP vacuum secondary Holley.

Last edited by cobalt327; 12-03-2011 at 12:33 PM.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 12-03-2011, 01:02 PM
lakeroadster's Avatar
Hot Rods are Built, not Bought
 

Last journal entry: Lakeroadster's '31 Model A Tudor
Last photo:
Join Date: Dec 2001
Location: High Plains - Rocky Mountains
Age: 53
Posts: 695
Wiki Edits: 0

Thanks: 38
Thanked 106 Times in 96 Posts
Quote:
Originally Posted by cobalt327
Sometimes guys mistake a dual feed for a double pumper. There's no DP vacuum secondary Holley.
Well said.... my bad. I stand corrected.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 12-03-2011, 03:31 PM
1996thunderchicken's Avatar
ALL AMERICAN MADE
 
Last photo:
Join Date: May 2011
Location: il
Age: 28
Posts: 128
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
i took the old edelbrock apart and found what i was thinking a bunch of crud under the float bowls and also found there was really small jets and rods in it like the guy was trying to get it to get the best economy the primaries were smaller than what was supposed to be in it and i ran the numbers it is 600 cfm but the jets looked to be from a 500 could of this been my problem im going to put in the .100 jet for the primaries and the .095 jets for secondaries and the rods i have to get are the .070X.047 so im not sure what dude was shooting for and if this dont work yea il probably try to find a qjet i used to have several but i got to look in my inventory k thanks a bunch any more help would be much obliged thank you and i will keep you up dated and as far as my wifes van im thinking ecm it was throwing the code for it its that or a cam sensor or fuel pump one or another lol
Reply With Quote Quick reply to this message

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:
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
153 tooth Chevy flywheel in an original '55 Chevy 3 speed stick. Classic Chevy Dave Engine 2 09-17-2010 04:44 PM
newer chevy distributer in older chevy car,what are these four plugs? gearjammer38 Electrical 11 08-09-2010 11:15 AM
Putting a 72' chevy 350 into 1995 chevy silverado that has a 4l80e trans Willbee26 Transmission - Rearend 3 03-28-2010 11:40 PM
chevy camaro vs chevy pickup bolt pattern old fords Transmission - Rearend 2 09-19-2008 07:07 PM
1986 305 chevy vs. 1987 305 chevy new style small block mtinsley Engine 2 08-22-2003 12:55 PM


All times are GMT -6. The time now is 06:29 PM.


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.