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HEI advance curves

Discussion in '1969-1972 K5 Blazer | Truck | Suburban' started by TED, Dec 18, 2002.

  1. TED

    TED Registered Member

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    I had a problem with my mechanical advance, the bushings on the weights were worn and the weights were getting stuck on each other. I bought a new advance kit made by Mr Gasket but after researching timing curves I'm not sure that any of the springs will give me a decent curve. Then again, the recommended curves I found looked like they were for high performance street motors. Anybody have any info on a good curve for a 350 with a mild cam and probably about 8.75:1 compression? The weights with the Mr Gasket set were lighter than my stock weights and even with the lightest springs in the set the advance curve was not quick enough to come close to the recommended curves I have found.
    TED
     
  2. Steve_Chin

    Steve_Chin 1/2 ton status

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    Foster City, CA, USA
    The exact curve you need depends on your camming and head design, but most 350s like something on the order of 34-36 degrees of total ignition lead at about 2600-2800 RPM. SHoot for something in that ball park.

    I hate those aftermarket weight and center plate setups. I bought a few of them and have found that the stamped weights are of questionable quality and the center plates just plain suck. I've found that their dimensional tolerancing is extremely poor. I wouold suggest hitting the bone yards and obtaining some wieghts and center plates out of some wrecked cars. You can find advance values for the varying center plates at: http://www.classicalpontiac.com/qa7/display.cgi?number=41074. If you don't want to mess with all of the boneyard garbage, contact Sun Tuned from that thread and he can set you up.
     
  3. TopOff

    TopOff 1/2 ton status

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    Location:
    Folsom, ca
    Get the crane cams adjustable springs and adjustable vacuum advance kit.

    You will need the factory plates though.

    Works GREAT!
     

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