Topic: Need help with choosing manifold and carb
in Forum: C3 Engines
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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
Former Member
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Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
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.
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
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.
Lifetime MemberModerator
Moses Lake, WA - USA
Joined: 4/16/2005
Posts: 2134
Vette(s): 1976 L48 4-spd, Mahogany Metalic exterior, Buckskin interior 350ci/350hp, 3rd owner, fiberglass spring, 255/50-16's Torq-Thrust II
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.
suncountry 2010-02-06 10:17:25
Here are some pic's from an earlier thread
Go to my Flicker accopunt to see pix...
Jim
Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
Posts: 6812
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.
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.
LukesVette 2010-02-07 08:20:15
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.
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