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  1. #1

    Default 2004 Silverado: 4.3L to SBC swap has began


    Here is my engine swap thread. 2004 Silverado 4.3L to 357ci built SBC.

    Day One: Sept 6th,08

    Prepped the truck, removed a few body panels that would be in the way. Drained the coolant, disconnected the battery.

    Unbolted the Y-pipe from the headers. Disconnected all of the engine sensor harnesses. Unbolted all of the bell housing bolts. (So I had thought) Removed the radiator hoses. Took off the accessory brackets, Alternator & P.S. pump. Removed the starter and disconnected the torque converter from the flexplate.

    Transfered the accessory brackets, studs & bolts over to the SBC. Modified the A/C bracket to clear the valve covers. Spaced the A/C compressor to also clear the VC's.

    Vortec 357ci Small Block Chevy: Big cam, high stall, long headers, rear gears. The typical formula.

  2. #2


    I've got a jack under the trans, and hooked up the cherry picker to a chain bolted to the 4.3L. Began to lift to seperate and the engine wouldn't bust loose... I had forgot two bell housing bolts, one on each side. And they are being a pain in my ass. One bolt has the fuel lines bracket on it... and the other bolt has a bracket holding a big thick wiring harness attached to it.

    In hopes of giving myself some more room between the back of the 4.3L and the firewall I removed the nut on the trans mount and jacked the tailshaft of the trans upward. I'm just taking a breather now... it's rough out there in the 90+ degree heat from the Arizona sun.

  3. #3


    Day 2. Sept 07,08:

    It's not 100% bolted in... lets call it 80%

  4. #4


    I didn't have any intention to get the motor in today, but my buddy and I watched this little cloud directly above us balloon into a massive thunderstorm and we got the engine sitting in the engine bay just as it started to down pour.

    The engine isn't completely on it's mount brackets. I have a feeling the trans slid forward in it's elongated slot on the cross member, enough to misalign the motor mounts up front. And the engine will sit 1.5" lower once it's completely on the mount brackets.

    I've got a couple more bell housing bolts to tackle, they needed to be changed out from metric bolts to 3/8" course. The TC needs to get bolted to the flex, started motor bolted up. Needed new starter bolts, from metric to standard.

    Still need to finish wiring in the new fuel injection harness and plug in every sensor harness.

    And,The K&N FIPK for 4.3L did not need to get modified at all to fit on the V8

    We also mounted the secondary trans cooler. Yes I know, I have some aligning to do... of the bumper cover and the cooler.

    Cheers ~Mykk

  5. #5


    Looking Good.
    6" BDS Suspension Lift / 3" Body Lift / 38x15.50x20 Dick Cepek FCII on 20x12 Dick Cepek DC-1 (summer set) / 325/80/16 Dick Cepek FCII on 16x8 American Racing Diamond Back (winter set) / Hypertech Power Programmer III / Air Max Spiral Flow Air Intake / / 80mm Granetelli MAF / 80mm BBK Throttle Body / Helix Power Tower Plus Throttle Body Spacer / 2 Turbonators / Edelbrock Shorty Headers / 30 Series Flowmaster / 4.56 gears /

  6. #6

    dwill3015's Avatar
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    Jan 2007
    Yacolt, Washington
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    That's an awesome write-up! Can't wait to see the finished result.
    Washington State
    2006 Silverado 2500HD LT3 4X4 CC SB Duramax LBZ
    Tuff Country 6" lift, 35" Toyo M/T's on 20" Ultra Peacemaker wheels, Quadzilla Stealth2 programmer, Diamond Eye 5" cat-back exhaust, factory Special order color Yellow.

  7. #7


    Looks great, keep up the good work and keep us updated. Look forward to more info!

    10 Chevy Traverse LT AWD
    02 Chevy Trailblazer LS (110K+ miles - loaded except for 4WD - WRECKED!)
    99 Chevy Cavalier LS (105K+ miles - commuter car)
    78 Chevy Suburban Silverado (454, 3/4 ton)
    62 GMC 3/4 ton Pickup (350 police interceptor)

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  8. #8


    Day 3. Sept 8th.

    Just taking it easy and going slow. I have a few appointments today that are keeping me from completely dedicating myself to the truck today.

    My hopes of just having the transmission mount slid forward and giving me the misaligned motor mounts were wrong. The trans was all the way back in the slot on the crossmember and I was about 1" from having the motor mount bolt holes line up.

    So I went with the first idea that came to mind. Elongate the transmission crossmember hole even more so the entire rotating assembly can slide back enough to compensate for how far off the motor mounts were.

    And it worked! The engine is now bolted down and sitting at the correct level.

    It's funny looking at the V8 with the 4.3L intake & TB & accessorys... it looks like I still have the six cylinder in there.

    Check out all that room I still have too.

    Cheers ~Mykk

  9. #9


    wow thats awesome. Can't wait to see it finished!
    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

    If you have any questions or problems don't hesitate to send me or any other GMTC moderators a PM

  10. #10


    Looks great man!! Can't wait to see to see the finished product!
    Hallsville, TX

    2005 Silverado 1500 LS Crew Cab 5.3L 2WD
    Magnaflow Exhaust
    Hypertech Max Energy Programmer
    Suspension Leveling Kit
    Putco Element Window Visors
    Carriage Works Billet Grille
    TruXedo TruXport Tonneau Cover

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