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Chevy 350 Rebuild

Discussion in 'GM Powertrain' started by zachh1020, Mar 15, 2009.

  1. zachh1020

    zachh1020 New Member

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    Hey everyone. A bud got me a Chevy 350 Small Block for free out of a wrecked truck ('89 or '90). I plan on a performance rebuild. I have 2 questions...

    1. Can anyone suggest a good Rebuild kit for this engine that will convert it into FI?

    and...

    2. How easy (hard?) would this engine fit and connect into my 2003 Silverado? (4.8L V8 Currently)


    Thanks in advance for the help!
    Z :glasses:
    #1
  2. KirkW

    KirkW New Member

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    I once replaced the 5.0L V8 in my old '86 Suburban for a 5.7L from an older truck.

    They're both Chevy small-blocks - how hard could it be?

    Well, '86 was the first year of the new rear-main seal appliance - which meant the flex-plate didn't fit. Luckily the older 5.7L came with a flex-plate.

    But the 5.7L didn't come with a dipstick - the mounting for that changed, too. On one engine the dipstick came out at the top of the block, on the other it came out from the bottom. It took a bit of bending to get the old one to fit the new engine, and was problematic enough that I considered whether or not I really needed a dipstick....

    Then there was the carburetor - I had to drill out the idle-jets and replace the main jets (or was it the metering rods?) to get the Rochester Quadrajet to properly feed the bigger displacement.

    In the end it all worked, but it was not a straight-forward, bolt-up replacement.

    In your case you're switching families - the 4.8 is a distant cousin of the 5.7. And getting the FI tuned for the bigger engine will take more than just a set of numbered drill bits. Having not done it, I can't say it's impossible. But based on my previous experience I think you'll find the task extremely difficult.
    #2
  3. zachh1020

    zachh1020 New Member

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    Would it be easier to keep it Carb?
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  4. Crawdaddy

    Crawdaddy Moderator

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    to move to fuel injection would require adding a whole ton of sensors onto the motor. It would also require a head change I think, since there's sensors in the heads. I would not recommend this unless you know a good bit about the chevy small block lineage and what sensors go where on the block and such... It would be easier to convert it to carb than to upgrade it to fuel injection. It's most probably throttle-body injection with obd-1 sensors.
    #4
  5. silveradotrailblazer

    silveradotrailblazer New Member

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    You might want to try and find a 6.0 from salvage yard as this will bolt in with fewer mods. The guys at Diablo can make a tune for your ecm. It may be more to purchase a salvage 6.0 but I think in the long run you will spend less than converting and rebuilding your 350. Alot of your sensors and wiring will work on the 6.0. I know one guy that changed out his 5.3 to a 6.0 (LQ9) in one day, hooked up all the 5.3 electronics and it started and drove away. He did have the guys at Diablo build a tune for the ecm later and the truck runs good. Also check out GMs 6.0 crate motors. There more money but they come with factory warranties. Scoggin-Dickey seems to have best prices on crate motors. Check em out.
    #5

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