RE: Need some carb help

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RE: Need some carb help

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RE: Need some carb help - 3/28/2008 7:21:04 AM

C3 Starship

Posts: 4814
Joined: 7/25/2006
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.....and better mileage.

_____________________________

1980 L-82 Fastback (forward too)
Mono composite front and rear.
Full adjust ride height and
response.
400+ hp, 454, M-22, 3.07

2007 H. D. Sportster, XL 883 EFI

http://i121.photobucket.com/albums/o225/C3Starship/HPIM0423.jpg

(in reply to Sweetness224)

Post #: 11

RE: Need some carb help - 3/28/2008 8:09:48 AM

Sweetness224

Posts: 35
Joined: 12/4/2007
Status: online

Thanks for all the info guys. When i get it out this next week or so since its starting to get nice around here... finally... I'm going to see if i can find out for sure what carb and intake it is exactly so i know where to go from there. Is there any specific spots where i can find some model numbers on the intake and carb?

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When you turn you car on, does it return the favor?

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Post #: 12

RE: Need some carb help - 3/28/2008 10:51:50 AM

wrwalke

Posts: 391
Joined: 11/1/2005
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Of course the other thing to check when you get the "stomp it bog down" symptom is timing. Not only base timing, but check the vaccuum advance goodies to make sure they are working ok. Often, the extra shot of fuel will arrive before the vaccuum can catch up enough to advance the timing to take advantage of it. Kind of a flooding while running kind of thing. Once the revs come up a bit, the vaccuum comes up too, and advances to make the burn.

bill.

(in reply to Sweetness224)

Post #: 13

RE: Need some carb help - 3/28/2008 11:01:19 AM

Sweetness224

Posts: 35
Joined: 12/4/2007
Status: online

Thats another good point, but i had a local classic car resto shop work the timing which made it run better but still has that bog in it. So i think the timing is okay. I'll have to double check that though.

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When you turn you car on, does it return the favor?

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Post #: 14

RE: Need some carb help - 3/28/2008 8:37:10 PM

73shark

Posts: 1129
Joined: 4/18/2006
Status: online

If you don't want to go back to stock, I'd check Edelbrock cuz they have some good dual plane manifolds and their version of a Q-jet which is supposed to have some improvements. Of course you need to know if your cam is stock too because if the PO put a single plane manifold on with a big honkin' carb, he might have put in a cam to take advantage of them.

If you do decided to go stock, I can look up the P/Ns for you. They may be outdated but your parts guy can probably get an updated number. Of course they may no longer be available which means the search is on. That's half the fun.

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Post #: 15

RE: Need some carb help - 3/28/2008 9:07:46 PM

Wedge

Posts: 229
Joined: 11/3/2005
Status: offline

I am probably risking a butt chewing from my friends here... but here goes. If it all possible try to find a manifold with the same height as a stock one. Single planes do work best at higher rpms, but I believe Edlebrock is making a new style double runner that is low enough to fit under a stock hood. I used a taller Edlebrock two plane mainfold on my 454... and opened a huge can 'o worms trying to shoehorn it under the hood. I had to use drop base air cleaner from a '69, and finally found a 2.5' taller stock style hood that would clear the intake. These guys are right on carb size also, 650 max is all you need. If you decide to go with the Edlebrock, order the off road spring loaded needle seats, it helps keep the right amount of fuel in those side mounted float bowls. You will definately see the difference when you accelerate. You might also want to check into a Pertronix Ignitor II breakerless ignition kit and a hotter coil. A hotter spark than stock means better burn in the cylinders. Worked for mine!

(in reply to 73shark)

Post #: 16

RE: Need some carb help - 3/28/2008 9:26:36 PM

73shark

Posts: 1129
Joined: 4/18/2006
Status: online

Like I mentioned before, you can use a carb in the low 700 cfm range if it uses vacuum secondaries. The original Q-jet was around 730. I can't remember the exact number and too late to look it up.

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So many toys, so little time

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Post #: 17

RE: Need some carb help - 3/29/2008 5:25:05 PM

riley6riley

Posts: 119
Joined: 4/12/2007
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I have a 79 L-48 with some mods and a holly 600 is more than enough. With just a small block 350, I am still able to get a nice chirp out of the tires when shifting to the next gear. Stock 3 speed auto transmission. I have a different intake, it says performance on it I think and nice exhaust but I am not sure what is inside the engine.

The only draw back to the holly 600 is the fuel intake is on the driverside of the carb, meaning you have to run either a rubber fuel line from the fuel pump or manufacture a fuel line your self. I have the rubber fuel hose, not sure if they sell a metal one that will go from the fuel pump over to the driverside of the the carb.

(in reply to Sweetness224)

Post #: 18

RE: Need some carb help - 3/31/2008 4:08:44 PM

73shark

Posts: 1129
Joined: 4/18/2006
Status: online

As I have previously posted, GM used steel fuel lines for a good reason, to prevent fires. Since you can get steel tubing that already has the correct fittings on it, it's easy to make your own.

Just need to get a good tubing bender and the correct length of tubing and you've got a hard line from the pump to the carb. Highly recommended.

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Post #: 19

RE: Need some carb help - 3/31/2008 7:56:07 PM

Posts: 1066
Joined: 8/7/2006
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Hi Sweetness224, congratulations on getting a Vette on your own at a young age.
I thought that most stock Q-Jets were rated at about 750 cfm so 800 cfm is just a bit too large, ( someone may correct me on that ), when you first take off you are runing on the primary side of the carb, as rpm increases the secondaries start to open. At 3000 to 3500 rpm they are only open about half way, as you reach the red line they are still only open about 95%. Now you shift the secondaries close a little untill you again reach the red line, then you shift into high gear and near the end of the run everything ( primary and secondary are wide open).
73shark hit the nail on the head if you are not using vacuum secondaries than the they open too fast and your car bogs.
If you drive for fun a duel plane manifold and a smaller carb will give you a nice fast ride.
See if you can find out what stall speed your converter is and what rear gears you have, and do you have headers?
PG.

(in reply to 73shark)

Post #: 20