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CRATE GREAT but flat at 2K?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by high&liftedup, Jan 16, 2002.

  1. high&liftedup

    high&liftedup Registered Member

    Joined:
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    Location:
    CA
    My new 350 crate is up and many thanks to those with inputs. The throttle response is great but I did notice a slight 'flat spot' at ~2k...
    Engine: Comp cam (12-235-2), Edelb. Q-jet {new}, all MSD, headers/flows
    Timing is ~12deg. gap @.045.

    Now my questions to those who tweek for performance:
    1) Is this due to a new engine? In other words, wait until the motor is broken in?

    2) I have a MSD dist. with the heavy silver springs. Would changing the springs (vac advance) to the lighter blue springs help with this flat spot.

    3) Is this a carb issue?? (not dialed in)

    4) Am I tripping?? ( My old motor had a Edel. perfomer carb and it believe it responded better in the 2k area, BUT hated it during hill climbs)

    ...thanks for any inputs...........

    HE will always get you out of the mire clay!!!
     
  2. loudnowlouder

    loudnowlouder 1/2 ton status

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    Location:
    Ellicott City, MD
    i'm no expert, but i had a very similiar problem with my crate 350HO i put in a year ago. i know personally once the engine was broken in it ran much better, the idle was smoother, much more power all over the band. once i changed the oil at 500 miles i retuned the carb and fine tuned the timing...
    so it may just be that your carb isnt dialed in quite right (but you should be able to tell pretty easily, it'd either be dumping gas if its rich or running hot if its lean)
    ...i'd say check the carb and wait till the engine is broken before changing the MSD springs....

    good luck
     
  3. high&liftedup

    high&liftedup Registered Member

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    Thanks.. you're probably right on the 'break in'. I did talk to a guy who changed his vac. advance springs and he said it made a huge difference in the 2krpm range. I'll wait it out for a bit then do the tweeking.......

    HE will always get you out of the mire clay!!!
     
  4. slider

    slider 1/2 ton status

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    Location:
    Whidbey Is. Washington
    I agree with the advance springs. You can get your distributor degreed to your motor. I bought a new Proform distributor and had a speed shop degree it for me. What a difference. I have smooth clean power, I can dial in up to 12 degrees of initial advance and not have detionation problems unless I pull my camper and then I run 10 degrees before top dead center. They will ask you allot of questions about the motor, cam, gear ratio, etc. so they can get a idea of what the truck is used for. The distributor and recurve only cost about 200.00. Money well spent.
     

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