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msd, spark plug gap

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  • msd, spark plug gap

    i put an MSD 6AL box and blaster coil on my scout, it has a 304v8 with a holly 500cfm carb and a small cam. it runs great but i was told i need to open the gap up to .60 to .75. i thought that was really big, but i noticed that my plugs are getting so hot its melting the boots of the wire to the plug. if i go to big will it hurt anything?just got the motor redone dont want to mess it up, how big should i go?

  • #2
    I'd go .060". How did you wire in your MSD?


    • #3
      opening should help

      I just had a similar bout when I installed a Jacobs Omni Pak. Recommended gaps ranged up to .075. On advice I got here, I opened the gap to .045. When I went out to change the gaps, I too found the plug boots starting to stick (melt?) to the plugs. Ended up having to replace two wires.

      Now the good news. The engine really smoothed out at .045 and, now, after driving it for a few days, my gas mileage has improved dramatically. This improvement is soley based on gas gauge observations but it is going down a whole lot less.

      One article by Mike Deschamps (I believe) recommended starting with plugs that were already factory gapped at .075 and working down rather than trying to gap a plug from .030 or .035 up to the larger gap.

      Good luck and be sure to let us know how it runs.

      By the way, any idea what size jets you're running in that 500? I thought the 500 might be a tad large for my stock 304 so I went with a new 350 instead. Still thinking about using the 500 to get the larger accelerator pump if I end up modifying the engine.


      • #4
        msd wireing

        the msd was easy to wire, the distributio wire and the old coil power wire got to the box. you need to run 1 12v powere wire to the box, than you run the 2 wires that come from the box to your coil it was to easy and helped a lot


        • #5
          carb jets

          think i'm running 65 in it now but this weekend i'm going down to 63 and think i;m going to go with a little smaller powere valve


          • #6
            55-60 is what I run


            • #7
              down to 63 size jets now but i get a big hesitation when i stomp it so got to work that out