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Camshaft specs

Discussion in 'The Garage' started by 1979jimmy350, Feb 24, 2006.

  1. 1979jimmy350

    1979jimmy350 1/2 ton status

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    Is there a place where i can find the specs for a stock cam in a 74 350, I am trying to figure out how EFI friendly the cam is that i have in my engine
     
  2. 3 on the tree

    3 on the tree 1/2 ton status

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    Which 350? My 74 engine spec book lists 6 different 350s. Exhaust lift varieis from .260 to .300. Intake goes from .2733 to .3066. Duration from 288 to 340. Overlap from 58 to 114 degrees. The 250 horse has the most rad cam. If you give me the last 3 letters of the engine number, I might be able to tell you which one.
     
  3. 1-ton

    1-ton 1/2 ton status Premium Member

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    If it is a stock camshaft from a 1974 350 engine (which is a carbureted engine), then it is not friendly at all. Remember, the "E" in EFI stands for Electronic...meaning computer controlled, which means this camshaft will not work with a computer controled vehicle at all.
     
  4. 1979jimmy350

    1979jimmy350 1/2 ton status

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    is the stock shaft to much to handle with a little tuning or should i be fine with some tuning
     
  5. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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    Generally, too much overlap will allow a bit of unburned fuel past the exhaust valve at very low rpm (i.e. idle). The O2 sensor just reads the O2 content, sends what it sniffs to the computer, which figures that it's due to a lean condition (which it isn't, but the computer assumes a stock EFI-friendly cam), so it richens up the F/A mix - which makes things even worse.

    Aftermarket EFI systems (EB, Holley, etc.) are easily tuned to accomodate bigger cams, but the OEM comp is less user-friendly when it comes to bigger bumpsticks. There might be a few places that could burn you a new chip for your comp.
     
  6. 1985_K5_Silverado

    1985_K5_Silverado 1/2 ton status

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  7. dyeager535

    dyeager535 1 ton status Premium Member

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    Which system are you going to end up running, MAF or MAP?

    MAF is going to be "friendlier" towards the wrong cam, but it's still not going to be right.

    If MAF, personally I'd try it as is, hope for the best. I would expect to be burning your own chip or paying $$ to have someone else do it for you though, regardless of what it is. But as in my case, it may be "good enough" to let you drive the vehicle while you figure out which direction you want to go from there.

    BTDT, even if the cam is EFI friendly, the engine itself is entirely different than what the PROM is calibrated for, and timing and fueling is going to be wrong, (to what degree obviously depends on the engine itself) no matter how well the engine runs.
     
  8. 1979jimmy350

    1979jimmy350 1/2 ton status

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    i am going to run speed density, i already have a different prom chip for it. I have all the stuff and i burn my own chips
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    So you are set. I seriously doubt that a stock truck cam (if that is really what is in it) is going to be something that just won't work. Especially since you can burn your own. :)
     

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