Best burning plugs?

Discussion in 'Engine Topic' started by S_ghost, Nov 9, 2017.

  1. S_ghost

    S_ghost New Member

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    Aug 3, 2017
    Hey folks. I'm getting some things tweaked on a crate 383 in my camaro and apparently it has been burning too gas rich. The mix on the carb has already been leaned out to the point where it won't run in gear if we take it down any more. As I understand it the plugs that were used when the engine was dropped run hotter than a 383 stroker needs. The shop that put it in for me shoved autolites app5224 in it. Now I know putting the right plugs in it will cause a more efficient burn so, any recommendations as to what the right plugs would be? I've done some googling and have turned up next to nil...
     
  2. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

    moved for more eyes. I think folks might ask for more info.

    I like Delco and ngk plugs
     
  3. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Ringgold, GA
    That plug show as a double platinum 14 x 19mm (3/4") which is very common with aftermarket heads. Don't know why they used double platinum. I'm assuming you have a carburetor and HEI ignition? Can you provide some more info on engine combo, like specs on cam, heads, compression ratio, carb, ignition, etc. I have Eddy RPM heads, they recommend Champion RC12YC or equivalent 14mm x 3/4" reach with flat gasket seat, which is same specs as the Autolites. I'm actually using NGK BKR5EY on the street now.
     
  4. S_ghost

    S_ghost New Member

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    Aug 3, 2017
    Carb is a Holley 750.

    Cam Style: Hydraulic Roller tappet
    Intake Valve Lift: .528
    Exhaust Valve Lift: .536
    Intake Duration at 050 inch Lift: 221
    Exhaust Duration at 050 inch Lift: 226
    Lobe Separation (degrees): 110

    These are the heads
    https://www.summitracing.com/parts/mll-h8002k.
    I'm not sure of the compression
     
  5. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

    8,812
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    Nov 4, 2004
    Ringgold, GA
    Depending on piston type and how far they're down in the hole, somewhere in the 10 ~ 11:1, and that's just a wag. My 355 with flat tops, .010 below the deck, 64 cc Eddy heads, I'm in the 10.5:1 area. I've had real good luck with NGK BKR5EY (7390) plug. I have a Mallory HyFire 685 setup and for street use, gapped at .040.
     
  6. Dave Nelson

    Dave Nelson Veteran Member Gold Member

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    Dec 19, 2003
    Vineland N.J USA
    I switched to NGK years ago, use them in everything.
     
  7. ORANGE77

    ORANGE77 Veteran Member

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    TRAFFORD, PA.
    Same here with NGK. Those are on the Orange77. :)
     
  8. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    Mar 25, 1999
    San Jose, CA, USA
    I seriously doubt this is a plug-temp issue.
    When you say the carb has been leaned out to the point where it won't run in gear; did you just adjust the idle, or has the carb been re-jetted?
    What are your running for the ignition system?
     
  9. RS1979

    RS1979 Veteran Member Lifetime Gold Member

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    Jun 18, 2013
    Memphis, TN
    I would take a look at the jetting and nozzle sizes in your carb.
     
  10. PalmbchZ28

    PalmbchZ28 Veteran Member Gold Member

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