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Thread: Timing and advance for heavy truck

  1. #1
    Tuner in Training
    Join Date
    Mar 2023
    Posts
    18

    Timing and advance for heavy truck

    Hello everyone,

    I have an 83 Chevrolet C30 dually with an SM465 4 speed manual and Dana 70 rear end with 4.11 gears. In it is a 2004 5.3 from a Tahoe with the flex fuel injectors ad a returnless fuel rail. Other than that its all stock all the way to the air filter assembly. It's a heavy vehicle and I've been using the HP Tuners repository to compare timing tables from 2500 suburbans and pickups to help get me where i need to be as far as trying to make changes where necessary to compensate for the heavy weight. If i post my recent tune would anyone mind checking it out just to ensure that i have made the necessary changes? The truck is low geared so it does not see interstate use and very little highway use. Maximum i would have the truck up to is around 60-65 mph. But i will use it for pulling and it needs to be correct.

    8.25.Changes.new.plus.old.revised.hpt

    Thank you in advanced for any and all help

  2. #2
    Advanced Tuner
    Join Date
    Dec 2019
    Location
    MS
    Posts
    506
    What fuel octane? What Spark Plugs?

  3. #3
    Tuner in Training
    Join Date
    Mar 2023
    Posts
    18
    I'm running mid grade 95 octane and the factory AC Delco spark plugs

  4. #4
    Senior Tuner
    Join Date
    Nov 2017
    Posts
    1,083
    Sounds like OP is likely in a non North America location so "mid grade 95" is likely US 89 or so.