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1.6 ratio roller rockers on stock TBI?

Discussion in 'The Garage' started by sled_dog, May 21, 2003.

  1. sled_dog

    sled_dog 1 ton status

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    Would 1.6 ratio roller rockers be a performance improvement on a stock 90 tbi 350? Stock cam, will have some intake mods such as open element intake, tbi spacer, and ported throttle body. Will also have true dual exhaust with full length headers.
     
  2. BlazerGuy

    BlazerGuy 3/4 ton status

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    Yes since increasing the ratio will give you more overall valve lift without changing cams. To figure out the valve lift just multiply you cam duration by the rocker ratio(ex. .340 x 1.6). I'm not sure just how much improvement there will though since the stockers are 1.5...
     
  3. SUBFAN

    SUBFAN 1/2 ton status

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    Multiply the LIFT from cam by 1.5 and 1.6 to see the difference....
     
  4. sled_dog

    sled_dog 1 ton status

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    Anyone know the stock numbers for the factory cam?
     
  5. MousePowrd

    MousePowrd 1/2 ton status

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    [ QUOTE ]
    Anyone know the stock numbers for the factory cam?

    [/ QUOTE ]

    Very small
    I say go for it. Your engine is not computer controlled so you have nothing to jack up. Also stock Chevy lifters are famous for having ratios as small as 1.45:1 and as high as 1.55:1 when actually measured. Dont go over 1.6:1 though, as the gains diminish rapidly with a stock engine
     
  6. sled_dog

    sled_dog 1 ton status

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    no this is for my new truck a 1990 GMC so that is computer controlled. THats the other question, will it mess with the computer?
     
  7. MousePowrd

    MousePowrd 1/2 ton status

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    That depends on what other mods you have done to the engine. By itself the rockers wont screw with it, but add in headers, spacers, intakes, blah blah it eventually throws the computer off. I see you have a 355 so thats a little more airflow there, not much but it adds up

    Since you have other mods in mind, you will probably have to spring for a custom chip to be burned for your engine. Wait until everything is done before doing this
     
  8. sled_dog

    sled_dog 1 ton status

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    hehe again this thread is about something other than the K5 in my signature. Yeah maybe I will be getting a chip cause i am doing intake stuff and headers and exhaust.
     

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