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350 TBI Question

Discussion in 'The Garage' started by SF87K5, Dec 15, 2003.

  1. SF87K5

    SF87K5 1/2 ton status

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    Does anyone know what the Compression Ratio and the Throttle Bady's CFM is on a stock 1990 350 TBI?
     
  2. chevystepside

    chevystepside 1/2 ton status

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    i think about 8to1 compression and 500cfm all stock
     
  3. SF87K5

    SF87K5 1/2 ton status

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    chevystepside thank you.

    Can anyone conferm this at all.

    I am tring to figure my cam and crank build up on desktop dyno is why I need to know.
     
  4. Thunder

    Thunder 3/4 ton status

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    He's pretty close
    My book says 8.2 to 1 and 480- cfm is more realistic on the stock 1 11/16" TBI. But you can get them up to around 550 with a few cheap mods
     
  5. k20

    k20 3/4 ton status

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  6. SF87K5

    SF87K5 1/2 ton status

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    Well I just found out that the 350 has been already bored .030 over.
    So I will be building a 383 stroker TBI in about a year. /forums/images/graemlins/thumb.gif
    The mods that I will do is get a 400 grank, Comp Cams Xtreme 4x4 roller cam X258HR, Roller tip rockers, and all realed parts for the cam and crank, Air Flow Research 180cc intake port that are eather a 68cc or 74cc combustion chamber with a 64cc exhaust port and a 3/4” thick head deck. Also the holley 670 CFM TBI replacment, and a set of large headers. /forums/images/graemlins/thumb.gif

    Yes I know there are other stuff I will need and dont have on the list. But those are the big and high end items.

    Ben or Kelly I told you your guys info will not be a waste. /forums/images/graemlins/thumb.gif
     
  7. SF87K5

    SF87K5 1/2 ton status

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    Oh not sure what compression ratio I will run. It wont be anything over 9:1.
     
  8. Beast388

    Beast388 1/2 ton status

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    [ QUOTE ]
    Ben or Kelly I told you your guys info will not be a waste. /forums/images/graemlins/thumb.gif

    [/ QUOTE ]

    Good! It sound like you've got some good plans for that motor. It should scream!! /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  9. SUBFAN

    SUBFAN 1/2 ton status

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    With careful set up, you can run 9.5:1 compression with fuel injection....
     
  10. sled_dog

    sled_dog 1 ton status

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    anyone know what size combustion chamber stock TBI heads have?
     
  11. Beast388

    Beast388 1/2 ton status

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    [ QUOTE ]
    The mods that I will do is get a 400 grank,

    [/ QUOTE ]

    I would suggest buying a crank already machined for a 383. Most now days are made from nodualr iron which is stronger than the factory cast.

    [ QUOTE ]
    and a set of large headers. /forums/images/graemlins/thumb.gif

    [/ QUOTE ]

    I wouldn't get too big, you don't want to negate any low-end torque. I wouldn't go any bigger than 1-5/8" tubes with 3" collectors. /forums/images/graemlins/thumb.gif
     
  12. SF87K5

    SF87K5 1/2 ton status

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    Ben where can I get a 383 crank for the TBI also the 1 5/8 tubes with 3" collectors are the headers I am looking at. /forums/images/graemlins/thumb.gif
     
  13. Beast388

    Beast388 1/2 ton status

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    [ QUOTE ]
    Ben where can I get a 383 crank for the TBI

    [/ QUOTE ]

    I bought a Scat crank from Northern Auto Parts. There is one listed for your one-piece rear seal application here. /forums/images/graemlins/thumb.gif
     
  14. SF87K5

    SF87K5 1/2 ton status

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    Ben you think 1 1/2" tubes with 2 1/2" collectors will work pretty good for when I goto stroke it out?
     

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