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Topic: Need help with choosing manifold and carb

in Forum: C3 Engines


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Need help with choosing manifold and carb (1/12)
 2/1/10 5:07am
fowler12
Former Member

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Toledo, OH - USA

Vette(s):
1977 auto.L48 383 stroker


Joined: 2/22/2007
Posts: 175

I have a 77 L48 auto with the stock manifold and carb.  I need some help determining what a good aftermarket manifold and carb set up might be.  Thanks to all for your help!

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Need help with choosing manifold and carb (2/12)
 2/1/10 8:41am
gurtz
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baton rouge, LA - USA

Vette(s):
1981 dark metallic blue, dark doeskin leather interior, mirrored glass T Tops, 330hp/350ci GMPP crate engine, billeted aluminum serpentine system, Dewitts with dual spalls


Joined: 8/12/2006
Posts: 391

You could choose many set ups.  I went with the Edelbrock Performer polished manifold with the 600 cfm electric choke; however, if I could have fit an Edelbrock Air Gap, I would have done so.

 
Many folks love their Rochester, which I do also, but mine was toast.  Had it rebuilt, never was right, mainly due to the CCC in 81.  I have had several Rochester's and loved them.
 
So it is hard to say, it depends on what you are trying to do.
 
My .02 Good Luck
Need help with choosing manifold and carb (3/12)
 2/1/10 9:53am
Gunslinger
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Frederick, MD - USA

Vette(s):
1969 convertible L71 427/435 4-speed black interior


Joined: 9/8/2003
Posts: 3398

You have an L48...no matter what you'll do you won't see a huge increase in performance without cam and cylinder head changes or modifications.  You can do things with intake and carburetor that will make it be more responsive and smoother, though not necessarily much stronger.

The Edelbrock Performer is one of the few intakes that will work without causing clearance problems with the hood.  If you want to keep the stock Q-jet, it's a good choice....all fuel lines, vacuum lines and linkages will work as designed and simplifies installation.  The Q-jet is an excellent carburetor and one of the best for the street.  Have it rebuilt by someone who understands them and you should be quite happy.

If you want to change carburetors, get an Edelbrock Performer 600 with electric choke.  That's an excellent street carb in its own right...simple and holds adjustments.  If you go that route, get the Performer EPS intake manifold...it's designed specifically for and optimized for the Edelbrock square-bore carbs.  It has somewhat better horsepower and torque number than the standard Performer intake, but not by a lot.  

The downside to changing carburetors from the stock Q-jet is your fuel lines have to me modified some, the linkages will as well.  None of this is major, just needs to be taken into account.  If you have a/c, you'll need Edelbrock's proprietary a/c kick-up solenoid...it's different from the original.  All those changes add up to additional cost, so figure that in.  

Any of these choices will allow your engine to run smoother and stronger, and will wake your engine up a bit.  Don't expect miracles but you should be quite happy with the results.
Need help with choosing manifold and carb (4/12)
 2/1/10 10:21am
fowler12
Former Member

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Toledo, OH - USA

Vette(s):
1977 auto.L48 383 stroker


Joined: 2/22/2007
Posts: 175

Thanks guys, I appreciate your insight!
Need help with choosing manifold and carb (5/12)
 2/1/10 5:18pm
KDADDY79
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Dutchess County, NY - USA

Vette(s):
White '79 Corvette. It's a driver.


Joined: 8/27/2007
Posts: 2484

Matthew,
Mine is a '79 L-48.
I had my Q-Jet rebuilt at the Quad Shop (http://thequadshop.net/). The rebuilder, Jim McGowan, really knows his stuff with the Q-Jet. I was very happy with his work!
I also used an Edelbrock Performer Non-EGR intake manifold and put on a true dual exhaust system with no cats.
It'll never be a horsepower giant but I was real happy with the results!
Kevin
Need help with choosing manifold and carb (6/12)
 2/6/10 9:14am
roadbiker
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Powder Springs, GA - USA

Vette(s):
1981 2-tone Claret. 4spd transmission, cloth interior, Gymkanna suspension, Glass T-Tops, A/C, Alloy Wheels, 28,000 original miles, prize-winning car in new condition.


Joined: 8/5/2008
Posts: 42

I have an '81. I completed disabled the ECM system and replaced it with...
 
Edlebock Performer Intake Manifold (Polished)
Edlebrok 600 cfm Carburetor
MSD Ignition System with spark box
Hooker Headers and Custom X-Pipe Exhaust System (used stock mufflers)
 
Car runs 200% better, sounds better, and the Engine looks great.


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Need help with choosing manifold and carb (7/12)
 2/6/10 12:43pm
suncountryLifetime Member
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Moses Lake, WA - USA

Vette(s):
1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II


Joined: 4/16/2005
Posts: 2134

I am running an RPM manifold with a Berry Grant 650 dbl pumper carb. I had to go with a drop base air filter housing and I think the K&N is 3" tall. Just barely clears the hood. If you are not changing the heads or cam then I think the performer manifold would be a good bet. You might want to think about adding a set of GM steel Vortec heads. There not very expensive and would help the breathing.
I forgot to add I have a 1/2" carb spacer so the accelerator pump clears the manifold.
 
Here are some pic's from an earlier thread
suncountry2010-02-06 10:17:25
Need help with choosing manifold and carb (8/12)
 2/6/10 10:41pm
roadbiker
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Powder Springs, GA - USA

Vette(s):
1981 2-tone Claret. 4spd transmission, cloth interior, Gymkanna suspension, Glass T-Tops, A/C, Alloy Wheels, 28,000 original miles, prize-winning car in new condition.


Joined: 8/5/2008
Posts: 42

Go to my Flicker accopunt to see pix...

 
Jim


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Need help with choosing manifold and carb (9/12)
 2/7/10 11:19am
lukesvetteLifetime Member
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HOWELL, NJ - USA

Vette(s):
1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.


Joined: 5/18/2004
Posts: 6812

Before I did my motor change, I had a Performer RPM with an Edelbrock 600 CFM carb and it did clear the stock hood with a drop base air cleaner. When researching manifolds for my new 406, I learned that the RPM Airgap is the same height as a regular performer RPM. A phone call to Edelbrock also confirmed this.

So, if you do decide to go with an RPM manifold, keep the Airgap in mind. I separates the runners from the valley pan of the manifold, so the air/fuel mixture stays cooler than the rest of the manifold...

Airgap is in my signature below.
LukesVette2010-02-07 08:20:15
Need help with choosing manifold and carb (10/12)
 2/10/10 3:34pm
KDADDY79
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Dutchess County, NY - USA

Vette(s):
White '79 Corvette. It's a driver.


Joined: 8/27/2007
Posts: 2484

Hey Jim (roadbiker),
I just took a peek on your Flicker account.
Nice work!
Thumbs Up
Matt,
Let us know what you decide to go with.
Kevin
Need help with choosing manifold and carb (11/12)
 2/19/10 12:45pm
KeBo
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Kendall Park, NJ - USA

Vette(s):
1981 - 59 Beige over Cinnebar leather. Edlebrock top end, 2200 stall w/shift kit, 3:55s, Mufflex maniback exhaust, nice stereo, 16 in AREs w/BFGs


Joined: 3/9/2005
Posts: 789

Kev - I also went with a E-brock intake and carb. Same one recommended above. VERY important - You can shut your hood!  I have that combined with a total de-smog and mani-back exhaust and you can really feel it. Its like a diff car..  Kevin..
Need help with choosing manifold and carb (12/12)
 2/20/10 12:12pm
tuxblacrayLifetime Member
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Greensburg, IN - USA

Vette(s):
Previous: 1984 Silver / Charcoal Coupe, 1988 Maroon Coupe / 1989 Artic White Coupe / 2001 Speedway White Roadster / Present:1976 Stingray Black / Black, Auto, 350 slightly modified (355 hp) Luxor Wires Redline Tires. / 1989 Roadster Bright Red...


Joined: 9/24/2003
Posts: 5188

I run the Edelbrock Performer with the Q-Jet... Lotta folks change carbs but the Q-Jet has always been a favorite of mine and the seem to run pretty much maintenance free for me.

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