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  1. #1

    Default 1998 seirra 4.3 to 350 5.7?

    I have a 98 sierra with 5 speed vortec 4.3 and my friend is geting an 80s(i think) Chevy van with a 350 with 60k. From what I understand the 350 will bolt up to the transmission but will the mounts be the same or just use the 350 ones? Or will I need special ones?

    its carburated so the wiring should be easy?

    I can handle fabing up the exhaust.


  2. #2
    Legend

    Join Date
    Feb 2008
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    Red Wing, Minnesota, United States
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    Default

    not sure but i dont think the computer would do such a great job from trying to manage FI V6 to a carb V8, why not just et a vortec they are cheap and easy to find
    99 K1500 Suburban LT "THE BEAST"
    Hypertech III, K&N, true dual
    285/75/16
    ___________________________
    Jason

  3. #3

    Default

    The computer dont have to do anything it would just kinda hang out I guess?.... the point is that the motor is there for the taking...

    so is this not feasible?

    anyone else know about the mounts?

  4. #4

    Default

    sorry no help with that ..not really my dept.

    welcome though!!
    Ryan

    2002 Jeep Wrangler Sport 4x4 (the Yellow Jacket)
    4inch suspension 3inch body
    Straight 6 (383 Stroker within a year)
    36inch SuperSwamper TSL.
    105,000
    Detroit Loccers
    Daily Driver Weekend Wheeler
    much more...

    2004 Sierra crew cab, 2wd, 5.3 V8
    2inch Daystar Leveling kit
    single dumped Flowmaster 40 sieries exaust(removed)
    Mb Blitz Chrome wheels
    Leer Bed Cover(for sale)
    50k miles
    :glasses:




  5. #5
    Legend

    Join Date
    Feb 2008
    Location
    Red Wing, Minnesota, United States
    Posts
    3,390

    Default

    well the transmission needs the computer and everything would be off

  6. #6

    Default

    If you want to do that, find a TH700R4 transmission. It's the predecessor to the 4L60E and will bolt up and work happily with that 350 carbed. You WILL need a TV cable hooked up from the transmission to the throttle linkage and it MUST be set right. The TV is NOT a kickdown cable, and if treated as such, WILL cause imminent transmission failure. OK, enough of that. You will also have to swap fuel pumps or find a fuel pressure regulator since the fuel injected pump is putting out sometihng like 60PSI when carbs don't like much more that 10PSI without freaking out. Wait...which vehicle are you dropping this setup into? If you're dropping it into the 98 Sierra, you will have NOTHING, no gauges, no nothing. Everything relies off the computer, and if there's no motor and transmission to get data from, nothing will work.
    Christopher

    1991 Chevy Suburban 1/2 ton 2WD w/ chevy SBC 350-3/4 ton drivetrain upgrade w/4.10 gears 200K miles
    2005 Saturn ION-2 Stock 277K miles
    1982 Bronco, 1993 Bronco (sold), 1971 M35A2 Deuce and a Half



    There are 10 kinds of people, those who understand binary, and those who dont...

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  7. #7

    Default

    yeah I don't think that this is going to work out too well.
    Dan
    1999 GMC Sierra 2500 350 vortec
    1967 Jeep M725 ambulance 230 tornado
    1990 Cherokee Limited- 3 inch lift on 33's
    ...and every one of em has issues

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