6425 Digital 6AL Ignition Control Box with Built-In Adjustable Rev-Limit Control
InfoVehicle Info Needed
MSD IGNITIONPART NUMBER: 121-6425

6425 Digital 6AL Ignition Control Box with Built-In Adjustable Rev-Limit Control

$36495
More than 10 available
ShippingShips on Nov 02, 2026
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Street
Digital 6AL Ignition Control Box
  • Built-In Adjustable Rev-Limit Control
  • High-Output w/530 Volts & 135mJ of Spark Energy
  • Uses Less Current to Provide More Power
  • Built-In LED for System Checks
  • Red
  • CARB Approved
  • Sold Individually

    MSD 6425 Digital 6AL Ignition Control Box Features:

    • Compatible on 4, 6, or 8-cylinder engines with 12-volt negative ground electrical systems
    • Same bolt pattern as traditional 6AL but with low-profile housing
    • Delivers 530 volts to the coil with up to 135mJ of spark energy per firing
    • Efficient internals draw less current to produce more power
    • Set rev limit in 100 RPM increments with two rotary dials
    • All wires exit on the same side via a sealed/locked connector
    • Accepts trigger inputs from breaker points, amplifiers, and magnetic pickups
    • Includes wiring harness, necessary installation components, and vibration mounts
    • Built-in LED for system checks

    MSD 6425 Digital 6AL Ignition Control Box Specifications:

    • Spark Energy: 135 to 145 mJ
    • Primary Voltage: 520 to 540
    • Secondary Voltage: 45,000
    • Spark Series Duration: 20 degrees Crankshaft Rotation
    • RPM Range: 15,000 with 14.4 volts
    • Required Voltage: 12 to 15 (7-volt start)
    • Current Draw: 0.7 amp per 1,000 RPM
    • Size: 8 in. L x 4 in. W x 1.825 in. H
    • Weight: 1.7 pounds

    Emissions Note:

    This part is legal for sale and use on Emissions Controlled Vehicles, in all 50 states, when used in accordance with the manufacturer's application guide because it has California Air Resources Board (CARB) Executive Order (EO) number D-40-43

    CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART

    FAQ

    Does an MSD 6425 Digital 6AL have a rev limiter?

    • Yes, the Digital 6AL features a built-in adjustable rev limiter to protect your engine from over-revving, ensuring optimal performance and safety

    How do you set the rev limiter on an MSD box?

    • Setting the rev limiter on the MSD 6425 Digital 6AL is simple. Using the rotary dials, adjust the desired RPM limit with precision, offering control over your engine's maximum revolutions

    What is the purpose of an MSD Digital 6AL box?

    • The MSD Digital 6AL enhances ignition performance, providing higher spark energy for improved throttle response, smoother idle, and overall better engine power and efficiency

    Does MSD ignition make a difference?

    • Absolutely. MSD ignition systems deliver stronger and more consistent sparks, leading to better combustion, increased power, improved fuel efficiency, and smoother engine operation
    • 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 Height3.6
    Package Width7.4
    Package Length10.6
    Weight3.25 PG
    Part CategoryPerformance Parts
    Current Draw0.7 amps per 1,000 rpm
    Carb Eo NumberD-40-43 (pdf)
    ColorRed
    Rev LimiterYes
    QuantitySold individually
    Spark Output (Millijoules)135-145 Millijoules
    Secondary Voltage45,000 Volts
    Rpm11,000 RPM
    Ignition Box OutputCapacitive discharge
    Primary Voltage520-540 Volts
    Cd Voltage Output To Coil520-540 V
    Voltage Required12-15 Volts, 7 Volt Start
    Part FitmentUniversal
    Ignition Box ColorRed
    Vendor Part Number6425
    Package Qty1
    Package TypeEA
    No Questions
    No Reviews

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