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Product Summary

Capacitive Discharge Ignition Box Output, Red, Red

  • Features a higher output with 530 primary volts and 135mJ of spark energy
  • Efficient components use less current to produce more power
  • Two rotary dials allow you to set an RPM limit
  • Has the same bolt pattern as the original 6AL, but with a lower profile housing
  • Integrated LED lights for system checks

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Key Specs

D-40-43
MFG. Part #6425
BrandMSD
Ignition Box OutputCapacitive Discharge
CircuitryDigital
CARB EO#
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Need To Know

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MSD 6425 Details

The MSD 6AL Ignition Control set the standards that other ignitions strive to reach. In fact, you'll find ignitions from other companies that carry the 6AL name (and in some cases, the same part number). MSD raised the bar even higher with the revised Digital 6AL Ignition Control!

The wiring of the Digital 6AL is routed out one end of the unit through a sealed and locking connector. This eases installation and keeps your wiring looking neat and clean. The rev-limiter of the 6AL is located right on top of the housing for easy access to the two rotary dials to set the limit in 100 rpm increments.

Inside the Digital 6AL, you'll find a microprocessor that monitors and controls every firing and rev limit. The circuits are updated with efficient components that help the ignition produce more power while drawing less current! In fact, the Digital 6AL delivers over 530 volts to the coil with up to 135mJ of spark energy for every firing! Increased output combined with MSD's proven multiple spark series is a win-win situation!

The Digital 6AL is supplied with the wiring harness and the components you'll need for installation. The 6AL is also supplied with vibration mounts. Both ignitions are compatible on 4, 6, or 8-cylinder engines with 12-volt, negative ground electrical systems. They'll accept trigger inputs from breaker points, amplifiers, and magnetic pickups.

Features:

  • High output with 530 volts and 135mJ of spark energy
  • Efficient components use less current to produce more power
  • Set an rpm limit with two rotary dials in 100 rpm increments
  • Built-in LED for system checks
  • All wires exit through a locked, sealed connector
  • Compatible with 4, 6 or 8-cylinder engines

Learn more about determining the proper MSD ignition control box for your application by reading our tech article. MSD Ignition Box: Ignition Controller Buyer's Guide

Rebates

Holley IRS Sale 2026

Save 10% instantly on select products across the Holley family of performance brands during the annual Holley I.R.S.Tax Sale. Instant rebate period has been extended and now runs from February 17, 2026 through April 19, 2026.

MSD 6425 Specifications

D-40-43
KEY SPECS
MFG. Part #6425
BrandMSD
Ignition Box OutputCapacitive Discharge
CircuitryDigital
CARB EO#
GENERAL
Rev Limiter IncludedYes
Data AcquisitionNo
RPM Range11,000 RPM
Timing RetardNone
Coil IncludedNo
Primary Voltage520-540 Volts output to coil
Secondary Voltage45,000 Volts
Spark Output135-145 MJ
Voltage Required12-15 Volts, 7 Volt Start
Current Draw0.7 Amp per 1000 RPM
Ignition Box ColorRed
GTIN Code085132064250
Overall Length8.00"
Overall Width4.00"
Overall Height1.88"
ColorRed
Sold in QuantityEach
Emission Code1

Ratings & Reviews

5

18 Reviews

Overall Assessment

Customers strongly endorse the product for its high quality, practicality, and ease of installation. They particularly appreciate its simplicity and functionality. The product is universally heralded for working exceptionally well right out of the box, needing minimal adjustments. It is recommended for all applications, highlighting its broad usability. The product stands out for quality, with users frequently choosing it for building their motors. Its easy-to-follow instructions and similar mounting to earlier models were also positively noted. The product is recognized as the best choice among users, with several confirming they'll purchase again, and recommend it to friends.

5

19 reviews

5

19

4

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3

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0

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If needed I would definitely make this purchase again

5.0

11 days ago

Big Al

Fresno Texas

Verified

I rate this product very highly

Would Recommend

This is the only brand I use

5.0

9 months ago

Mach 1 Dude

Illinois

Verified

These work every time no matter which model you use

Would Recommend

Yes

5.0

11 months ago

Greg

Nebr.

Verified

Works great

Would Recommend

Love this box

5.0

a year ago

LMSS14

Sioux Falls, SD

Verified

Haven't used this one in my car yet, but have seen it in use in friends cars. Heard nothing but good things about it.

Would Recommend

I would buy this product again and again

5.0

a year ago

Quill

Pa

Verified

In all my time mess around with vehicles, I did not have a digital MSD box. I always used to use the old analog, I am convinced that the digital ones are a lot better

Would Recommend

yes

5.0

2 years ago

pags

south jersey

Verified

worked out perfectly

Would Recommend

Good value

5.0

2 years ago

Guy

Stevens point, Wi

Verified

Good quality

Would Recommend

I will buy this product again.

5.0

2 years ago

IRS

Schofield, Wi

Verified

Installed the distributor and 6AL, Hooked it up, worked out of the box! Made adjustments, up and running!

Would Recommend

Yes I would y this again!!

5.0

3 years ago

Sr. Piston

Ione,ca

Verified

Nothing went wrong, ordering was easy, shipping was great,ups, part is working great! Would definitely use speedway motors again

Would Recommend

I would highly recommend

5.0

4 years ago

Mike

Missouri

Verified

I like them for all applications

Would Recommend

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