Made in USA
6520 Digital 6-Plus Ignition Control Box
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MSD IGNITIONPART NUMBER: 121-6520

6520 Digital 6-Plus Ignition Control Box

$67895
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Performance
Digital 6-Plus Ignition Control
  • Per Spark Energy: 135 mJ
  • Built-in 2 Step Rev Limiter
    (One Stage of Retard and Start Retard)
  • CARB E.O Number D-722-2
  • Red

    Parts Breakdown

    The MSD Digital 6-Plus Ignition Control combines terrific power, digital accuracy, and great accessories making it ideal for street/strip applications. Every spark of the Digital 6-Plus Ignition is packed with 135 millijoules of spark energy and 535 primary volts. When used with the MSD Blaster HVC Coil (121-8252), a spark with over 300 milliamps burns across the plug gap for 400 microseconds. Below 3,300 RPM the Digital 6-Plus produces a series of sparks that burn in the cylinder for up to 20° of crankshaft rotation. This incredible heat ensures combustion to produce great power, quick throttle response, smooth idle, and fast starts.

    Highlights

    • Switch between two rev limits that adjust with rotary switches in 100 RPM increments
    • Single-stage retard for nitrous and top-end performance
    • Start retard eases pressure on the starter, flywheel, and engine
    • Adjustable magnetic pickup compensation produces accurate trigger signals
    • LED display warns of trigger signal problems or faulty charging system
    • Fully potted with polyurethane for vibration and water protection
    • Non-OBDII approved via CARB EO #D-722-2
    • 50 State Legal

    Operating Specifications

    • Spark Energy: 135 mJ per spark
    • Primary Voltage: 535 volts
    • Secondary Voltage: 45,000 volts (Tested with blaster HVC II coil)
    • Spark Series Duration: 20° Crankshaft Rotation
    • RPM Range: 12,000 RPM with 14.4 volts
    • Voltage Required: 12-18 volts (negative ground)
    • Current Draw: 0.7 amp per 1,000 RPM
    • Size: 8.5" L x 4.5" W x 2.2" H
    • Weight: 3.7 lbs




  • Switch between two rev limits that adjust with rotary switches in 100 rpm increments.
  • Single stage retard for nitrous and top end performance.
  • Start retard eases pressure on the starter, flywheel and engine.
  • Adjustable magnetic pickup compensation produces accurate trigger signals.
  • LED display warns of trigger signal problems or faulty charging system.
    • High-Output Ignition Boxes for Maximum Spark Energy

      MSD 6-Series Ignition Boxes set the standard for quick starts, increased power, smooth idle, crisp throttle response, and reduced spark plug fouling. MSD Ignitions Boxes are available in several styles and install easily in multiple applications.

      Show More

      Unlock the true potential of your engine with the MSD 6-Series Ignition Control Boxes, a trusted choice for performance enthusiasts and racers alike. Whether you're cruising on the street or running hard at the track, the MSD 6-Series delivers the high-energy spark needed for complete combustion and maximum horsepower.

      Built with reliability and power in mind, the MSD 6 Series ignition boxes feature capacitive discharge (CD) technology that produces multiple sparks during the combustion cycle, resulting in smoother idling, quicker starts, and improved throttle response. This multi-spark feature is especially beneficial at lower RPMs, ensuring more efficient fuel burn and fewer misfires.

      The MSD 6 Series Ignition units are housed in a durable, vibration-resistant aluminum case that’s ready for the rigors of street or strip. Easy to install and compatible with a wide range of engines and distributors, this versatile ignition box is a go-to upgrade for those looking to enhance overall engine performance.

      Whether you're running naturally aspirated or forced induction, the MSD 6 Series Ignition Control gives you the confidence of consistent spark delivery at high RPMs, helping your engine perform at its peak when it matters most. With several models available—including options for street, marine, and racing applications—there’s a 6-Series box tailored to your build.

      Choose MSD for proven ignition technology that boosts performance, improves efficiency, and ensures your engine fires strong every time.

      The MSD 6 Series Ignition Control Boxes are a cornerstone upgrade for performance enthusiasts seeking stronger spark energy, improved combustion efficiency, and reliable high-RPM performance. Designed to deliver multiple sparks at lower RPM and a powerful single spark at higher engine speeds, MSD 6 Series Ignition Control Boxes help maximize horsepower, throttle response, and overall ignition stability. Whether you’re building a street-driven muscle car or a dedicated drag racing machine, upgrading your ignition system is one of the most effective ways to improve engine performance and reliability.

      A high-performance ignition control box ensures a more complete fuel burn, which translates to smoother idle quality, quicker acceleration, and reduced misfires under load. For modified engines with increased compression ratios, aggressive camshafts, or forced induction, a robust ignition system is essential.

      Performance Benefits & Key Features

      MSD 6 Series Ignition Control Boxes are engineered to provide capacitive discharge ignition (CDI), delivering high-voltage spark output and consistent performance across the RPM range. Performance enthusiasts often evaluate ignition systems based on spark energy, rev limiter capability, wiring compatibility, and durability. The multiple spark discharge feature enhances combustion at lower RPM, improving drivability and fuel efficiency in street applications.

      These ignition control boxes are built with rugged housings to withstand vibration, heat, and demanding driving conditions. Adjustable rev limiting functions help protect engines from over-revving, making them ideal for both street performance and competitive racing environments. Improved spark intensity supports stronger combustion in high-compression and boosted engine combinations, contributing to enhanced torque capacity and throttle response.

      MSD 6 Series units are commonly used in street performance builds, drag racing cars, circle track applications, and classic muscle car restorations seeking modern ignition reliability.

      Fitment, Compatibility & Applications

      MSD 6 Series Ignition Control Boxes are compatible with a wide range of GM, Ford, and Mopar engines when paired with appropriate distributors and ignition components. Popular applications include Chevrolet Camaro, Chevelle, Ford Mustang, Dodge Challenger, and various small block and big block V8 platforms.

      Designed to integrate with aftermarket distributors and performance coils, these ignition systems provide flexibility across carbureted and select EFI applications. Proper installation ensures seamless compatibility and optimal performance gains.

      If you’re ready to strengthen your ignition system and unlock consistent high-RPM power, explore the MSD 6 Series Ignition Control Boxes at JEGS and equip your build with proven ignition technology trusted by performance enthusiasts worldwide.

    Part TypeIgnition Box
    Product LineMSD 6-Series Ignition Control Boxes
    BrandMSD IGNITION
    Package Height3.1
    Package Width9.7
    Package Length11.1
    Weight3.95 PG
    Part CategoryPerformance Parts
    Ignition Box OutputCapacitive discharge
    Rev LimiterYes
    QuantitySold individually
    Cd Voltage Output To Coil535 V
    Spark Output (Millijoules)135 Millijoules
    Part FitmentUniversal
    Ignition Box ColorRed
    Rpm12,500
    Vendor Part Number6520
    Package Qty1
    Package TypeEA
    No Questions
    No Reviews

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    Some parts are not legal for use in California or other states with similar laws / regulations
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