NEED HELP! Intake Manifold/Carb
Thread Starter
8th Gear
Joined: Mar 2011
Posts: 8
Likes: 0
From: HACKETTSTOWN NEW JERSEY
NEED HELP! Intake Manifold/Carb
Hi All,
I want to install a new Edelbrock peformer intake manifold and 600 CFM carb, but heard from other motor heads that I "MUST" change the cam as well. Is there any truth to this?
I want to install a new Edelbrock peformer intake manifold and 600 CFM carb, but heard from other motor heads that I "MUST" change the cam as well. Is there any truth to this?
Thread Starter
8th Gear
Joined: Mar 2011
Posts: 8
Likes: 0
From: HACKETTSTOWN NEW JERSEY
Thank you!!!! I was getting the feeling from all these motor heads I was speaking with that it would be a bad idea to change the stock manifold and carb without doing other modifications. I'm seriously having problems with the stock QuadraJet and want to enjoy the car this season. The motor is a completely stock 350 L48 and I was kinda looking for a bit better response from the pedal and hope the new intake and carb will help me somewhat!
Thankls again Stu's81
Thankls again Stu's81
Drifting
Joined: Aug 2009
Posts: 1,635
Likes: 8
From: Enid Oklahoma
Thank you!!!! I was getting the feeling from all these motor heads I was speaking with that it would be a bad idea to change the stock manifold and carb without doing other modifications. I'm seriously having problems with the stock QuadraJet and want to enjoy the car this season. The motor is a completely stock 350 L48 and I was kinda looking for a bit better response from the pedal and hope the new intake and carb will help me somewhat!
Thankls again Stu's81
Thankls again Stu's81
Drifting
Joined: Sep 2010
Posts: 1,412
Likes: 50
From: Laguna Niguel California
I agree with 81pilot, you are going to have to change heads and cam to get a significant power increase. Install good heads and cam and you can even stay with the stock manifold and Q-jet.
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Drifting
Joined: Jul 2005
Posts: 1,562
Likes: 2
From: Spring Texas
The original Quadrajet carb for your car is rated 750 CFM. The issue with your car is that the stock heads restrict air flow. The OE cam was meant to work with those heads so it is lacking in performance, and yes, the stock low rise manifold is restrictive too. A good rebuild, and some rejetting, and the Quadrajet will handle quite a bit more HP. Cam and intake replacement combined with carb rejetting, will yield only modest gains in performance without upgrading to better flowing heads.
Of course then the question of how much HP your lower end can handle leads you to a new set of higher compression pistons, maybe even a forged crank, high performance rods and fully balanced rotating assembly, and if you don't already have one, a four bolt main block. Once you feel the need for more HP, you just won't be happy until you have a new 508 monster motor sitting under the hood.
Its a good idea to figure out how much more power you want, and spend the money to do it right the first time.
Of course then the question of how much HP your lower end can handle leads you to a new set of higher compression pistons, maybe even a forged crank, high performance rods and fully balanced rotating assembly, and if you don't already have one, a four bolt main block. Once you feel the need for more HP, you just won't be happy until you have a new 508 monster motor sitting under the hood.
Its a good idea to figure out how much more power you want, and spend the money to do it right the first time.
Racer
Joined: Nov 2009
Posts: 285
Likes: 9
From: Waukesha Wi
The guy asks if a manifold and carb can be installed without a cam change and everyone ASSumes he wants to completely rebuild his engine?
He said he wants better throttle responce,no where does he say he's looking for better/more performance.
He said he wants better throttle responce,no where does he say he's looking for better/more performance.
Drifting
Joined: Aug 2009
Posts: 1,635
Likes: 8
From: Enid Oklahoma
Thread Starter
8th Gear
Joined: Mar 2011
Posts: 8
Likes: 0
From: HACKETTSTOWN NEW JERSEY
Gentlemen you are all AWESOME and I respect all of your GREAT replies! I need to do as 71 rdster mentioned and think about what it is that I truly want so I get it right the first time and NOT waste money foolishly. I was not aware that my stock Quadrajet was in fact a 750 CFM carburetor. That being stated, I will NOT be purchasing a 600 CFM Edelbrock. I found a rebuilder that is supposed to be the "BEST" in the industry as far as rebuilding Quadrajet carburetors. His web link is:
http://quadrajetcarburetors.com/index.html
if anyone is interested. I thought he was a bit expensive and so I found another; http://www.nationalcarburetors.com/
They also claim to be a "GREAT" second generation rebuilder. There is absolutely too many choices thanks to the internet! Does anyone have any firsthand experience with a carburetor rebuilder that I could send my Quadrajet to?
I thank you all for your collective experience and abilities and look forward to at least getting my 77 Vette running smooth for the Spring/Summer & Fall seasons that are upon us!
http://quadrajetcarburetors.com/index.html
if anyone is interested. I thought he was a bit expensive and so I found another; http://www.nationalcarburetors.com/
They also claim to be a "GREAT" second generation rebuilder. There is absolutely too many choices thanks to the internet! Does anyone have any firsthand experience with a carburetor rebuilder that I could send my Quadrajet to?
I thank you all for your collective experience and abilities and look forward to at least getting my 77 Vette running smooth for the Spring/Summer & Fall seasons that are upon us!
Melting Slicks
Joined: Apr 2002
Posts: 2,337
Likes: 14
From: Norfolk VA
I haven't edel 1406 600cfm card sitting on my vette engine and a performer intake, and later edel rpm heads. I did not know better at the time and I gave away my q-jet. I have a mighty demon 750 and a stealth manifold that I was saving for a later engine build. I wiped my cam so I'm buying another one and I'm going put the stealth intake on it and then retire that non performing edel afb. Qjet is a good carb when properly tuned and a lot of forum members (myself included) do not know how to properly rebuild one, let alone tune it.
Melting Slicks
Joined: Jul 2005
Posts: 3,389
Likes: 83
From: Norfolk Virginia
Gentlemen you are all AWESOME and I respect all of your GREAT replies! I need to do as 71 rdster mentioned and think about what it is that I truly want so I get it right the first time and NOT waste money foolishly. I was not aware that my stock Quadrajet was in fact a 750 CFM carburetor. That being stated, I will NOT be purchasing a 600 CFM Edelbrock. I found a rebuilder that is supposed to be the "BEST" in the industry as far as rebuilding Quadrajet carburetors. His web link is:
http://quadrajetcarburetors.com/index.html
if anyone is interested. I thought he was a bit expensive and so I found another; http://www.nationalcarburetors.com/
They also claim to be a "GREAT" second generation rebuilder. There is absolutely too many choices thanks to the internet! Does anyone have any firsthand experience with a carburetor rebuilder that I could send my Quadrajet to?
I thank you all for your collective experience and abilities and look forward to at least getting my 77 Vette running smooth for the Spring/Summer & Fall seasons that are upon us!
http://quadrajetcarburetors.com/index.html
if anyone is interested. I thought he was a bit expensive and so I found another; http://www.nationalcarburetors.com/
They also claim to be a "GREAT" second generation rebuilder. There is absolutely too many choices thanks to the internet! Does anyone have any firsthand experience with a carburetor rebuilder that I could send my Quadrajet to?
I thank you all for your collective experience and abilities and look forward to at least getting my 77 Vette running smooth for the Spring/Summer & Fall seasons that are upon us!
Last edited by dprinter1; Mar 29, 2011 at 12:11 AM. Reason: Typo
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
If you want a quality rebuild on it send it to Lars. The carb might be fine. I have found most assumed carb problems to actually be ignition related. I picked up a full second in the quarter mile with a distributor recurve and vacuum can change. There was nothing wrong with the distributor other than the factory curve. Lars does the distributor rebuild/ recurve also and his work is second to none and very fairly priced. Check plugs, wires, points and advance curve before you mess with the carb always.
