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98 chevy 5,7 vortec to carb

This is a discussion on 98 chevy 5,7 vortec to carb within the Performance forums, part of the General Discussion category; well one of my heads went out or atleast the valves on cylinder one,,,it has zero compression,,,my freind recomends me ...

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    98 chevy 5,7 vortec to carb


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    well one of my heads went out or atleast the valves on cylinder one,,,it has zero compression,,,my freind recomends me machining the heads whihc is finw with me but i want to convert it to carb, what parts do i need and what would be a good combo the truck is for crusing and shows...but of course i want it to perform good aswell thank you

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    Cars & Guitars 04SilveradoMykk's Avatar
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    Re: 98 chevy 5,7 vortec to carb


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    Re: 98 chevy 5,7 vortec to carb

    sweeett thanks man....do u think the value packs are good from summit....i really want it to be reliable im afraid it wont run as good as it foes now....but will be stoked if it runs better

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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by 98extgreen View Post
    i really want it to be reliable im afraid it wont run as good as it foes now
    Do you know how to properly tune a carb and set up a timing curve?

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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by 04SilveradoMykk View Post
    Do you know how to properly tune a carb and set up a timing curve?
    no i dont

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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by 98extgreen View Post
    no i dont
    I suggest you do a ton of research before committing yourself to the carb idea.

    If you simply just bolt on and fire up you will be disappointed.

    However. if you carefully select the right size carb for your engine, and the right design carb for your tuning style. And dial in the right timing curve for your motor, the power on demand will make you very happy.

    Just a few suggestions from my personal experience:

    Look into using a Summit 8500xx series distributors, it's moderately priced and tunable just like an MSD. But I believe most of them need an ignition box to function.

    Edelbrock carbs for reliability and less fuel consumption, Holley carbs for power & performance and sucking gas. Edelbrocks are more complicated to tune than holleys but you change rods & jets without taking the carb off the motor.

    I would recommend the Edelbrock RPM air-gap for any street driven motor, especially if your keeping the factory 1997 valvetrain and stall converter. Make sure any intake manifold your looking at says it's for Vortec heads, they use a different bolt pattern and intake runners are raised higher. If your building for high rpm screamer, with a

    The timing curve: Max 36 degrees mechanical advance all in by 3200rpm (you change that with springs), bigger duration cams need more initial idle timing (you chance that with a bushing)

    Most old school hot rodders will tell you to plug the vacuum advance into a manifold vacuum not ported.(ported vacuum on the carb only gets vacuum above idle) Different engines respond differently to this, and might not work for you. But if you do decide on manifold vacuum for the advance, make sure you choose a vacuum advance can that is maxed out by the idle vacuum reading of your engine.
    Last edited by 04SilveradoMykk; 09-13-2009 at 09:48 AM.

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    Supporting Gold Member GreaseDog's Avatar
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    Re: 98 chevy 5,7 vortec to carb

    so you have zero compression on the number one cylinder, and your solution is putting a carb on it?
    77 Chevy K20 - 80 GMC K2500 (in pieces)
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    Re: 98 chevy 5,7 vortec to carb

    You're setting yourself up to spend a ****load of cash for no gain and less reliability. Fix what you have and run it.

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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by GreaseDog View Post
    so you have zero compression on the number one cylinder, and your solution is putting a carb on it?
    no my solution is to fix it and also convert it to carb but im going 6.0 instead

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    Re: 98 chevy 5,7 vortec to carb

    carb on a 6.0????? plz tell me your joking

    1997 K1500 Built vortec 355
    transbuilderguy built 4L65E, yank, 14 bolt

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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by Busted Knuckles View Post
    You're setting yourself up to spend a ****load of cash....
    false. The total swap should be well under a grand. New distributor, new igniton box, and the manifold/carb combo.


    Quote Originally Posted by Busted Knuckles View Post
    ...for no gain and less reliability.
    False. Carbs will ALWAYS have better off idle throttle response when compared to the same flow EFI setup. This will cause a huge, drawn out debate I'm sure, but it's true. If you have the PROPERLY sized carb on the motor, and it's tuned the way it should be, the throttle response is instantly noticable. the problem is that 97% of people who bash carb setups, don't know how to tune/size the system properly.

    I would do the conversion, 100%, go for it man!
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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by chevy-aholic View Post
    false. The total swap should be well under a grand. New distributor, new igniton box, and the manifold/carb combo.




    False. Carbs will ALWAYS have better off idle throttle response when compared to the same flow EFI setup. This will cause a huge, drawn out debate I'm sure, but it's true. If you have the PROPERLY sized carb on the motor, and it's tuned the way it should be, the throttle response is instantly noticable. the problem is that 97% of people who bash carb setups, don't know how to tune/size the system properly.

    I would do the conversion, 100%, go for it man!
    and the 3% of us who do know how to properly size a carb to an application will tell you that you, and/or your tuner, are idiots for thinking that a carburetor is a better air/fuel mixing device than injectors, taking input from sensors at several different locations, properly fueling the engine at all times and under all conditions.

    not sure if you realize this or not, but a carburetor is nothing more than a metered vacuum leak.
    Last edited by GreaseDog; 09-14-2009 at 09:44 PM.
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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by GreaseDog View Post
    a carburetor is nothing more than a metered vacuum leak.
    With a ton of fuel thrown in. But, throttlebodys are also metered vacuum leaks... the air needs to get in somehow

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    Supporting Member brutal's Avatar
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    Re: 98 chevy 5,7 vortec to carb

    and another grand for a stand alone trans controler
    differnt fuel pump
    you gotta do away with the wiring harness, im sure thats alot of work, for the money used to convert to a carb, could be used towards a marine intake, and the gain would be much more worth it

    1997 K1500 Built vortec 355
    transbuilderguy built 4L65E, yank, 14 bolt

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    Re: 98 chevy 5,7 vortec to carb

    I've torn down several injected engines at 150K miles or so, most still have visible hone marks in the bores. Can't say the same for any 25K carb'd engine I ever tore down. Fuel wash down is a big problem with most carbs, even those set correctly.
    Why swap from what you have if it works?
    If you have your heart set on a 6.0, fix what you have and sell it and buy a truck originally set up for an LS. You'll be time, money and headaches ahead.

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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by 04SilveradoMykk View Post
    With a ton of fuel thrown in. But, throttlebodys are also metered vacuum leaks... the air needs to get in somehow
    with precisely metered fuel being injected to each cyliner...
    Last edited by GreaseDog; 09-14-2009 at 11:29 PM.
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    Re: 98 chevy 5,7 vortec to carb

    There is no way a carbed has better off idle throttle response over an EFI setup, if both setups are properly sized to its application.

    Nothing wrong with a carb in certain applications, but there are several reasons why no OEM vehicles use a carb.

    peace
    Pauly
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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by Pauly View Post
    There is no way a carbed has better off idle throttle response over an EFI setup, if both setups are properly sized to its application.

    Nothing wrong with a carb in certain applications, but there are several reasons why no OEM vehicles use a carb.

    peace
    Pauly
    The conversion to EFI over carb was not made for performance, nor was it made for simplicity. Manufacturers started experimenting with it in the late 70's due to the overwhelming burdens caused by the EPA in regards to emissions. They tried de-tuning carbs in order to abide by federal regs, but eventually the power was cut drastic enough to cause the general public to outcry for a different system. A carb give the engine EXACTLY the fuel it demands, at any RPM, by precisely metering fuel in relation to vacuum. This is where it is key to properly size the carb to the engine. If the carb's venturis and jets are correct for the amount of air flowing through it, then it will deliver a perfect air fuel mixture to be distributed evently between all cylinders.

    There is no difference in "wash-down" between a properly tuned carb setup and an EFI setup. The same amount of fuel/air is being delivered with both systems, so how can you draw the conclusion that carb is hard on the engine?
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    WILL WORK FOR PARTS! chevy-aholic's Avatar
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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by GreaseDog View Post
    not sure if you realize this or not, but a carburetor is nothing more than a metered vacuum leak.

    yup, and these rudementary, barbaric devices are so popular on race day why? I always thought that both racing and performance enthusiasts were always after the same goal of making their car go fast!! I think that someone needs to tell the hundreds-of-thousands of hot-rodders that they are idiots and clearly running the wrong setup.
    Projects: (click for link)

    496SS: Roots-Blown 496 BBC, Custom backhalf, Parallel 4-link, T316 Stainless exhaust "Dual Path" w/ dumps, Lots of fiberglass!!!
    "Stock appearence, Strip Performance!"


    The Jeep: SOLD!!

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    Cars & Guitars 04SilveradoMykk's Avatar
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    Re: 98 chevy 5,7 vortec to carb

    Quote Originally Posted by chevy-aholic View Post
    I think that someone needs to tell the hundreds-of-thousands of hot-rodders that they are idiots and clearly running the wrong setup.

    Well now, I have to disagree with you on this one... trust me, I am pro carb thats why I've got one on my '04 silverado... But most Hot Rodders are old guys, and old guys are generally afraid of fuel injection because they don't know how it works.

    But, than again... I always love this image.



    And dude, Pauly is the most intelligent man on all of thees automotive forums. Don't think you'll be telling him something he doesn't already know.
    Last edited by 04SilveradoMykk; 09-15-2009 at 12:42 PM.

 

 
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