MSD 6AL Ignition Box

Adding an ECU Ignition Control Box (MSD 6AL 6425)

My Ford 302 in my Cobra has a traditional points distributor, an MSD ATOMIC EFI/ECU system, and an MSD Blaster Coil, all of which work just fine. And to complement these, I've installed an MSD 6AL 6425 box... It was on my to-do list.  🤗

The MSD 6AL box provides a massive spark compared to the regular coil output 🤩, and will complement all sorts of things.

Examples include a better burn, better mpg, a few more horses, and a stabler idle (not that it's unstable!)

…And I get to tick it off my list.  ✅

6AL OVERVIEW: Inside the black box [which is red] is a microprocessor that monitors and controls every firing and delivers over 530 volts to the coil, with up to 135 mJ of spark energy.

Supplied with a wiring harness and vibration mounts, it accepts trigger inputs from traditional breaker points and magnetic pickups. The rev limiter is located on the top of the housing for easy access to the two rotary dials, allowing the idle to be set in 100 rpm increments.

  • Features:
    • All wires exit through a locked, sealed connector
    • Uses less current to produce more power
    • Built-in LED for system checks
    • Compatible with 4, 6 or 8-cylinder engines
    • The RPM limiter is set by two rotary dials in 100 RPM increments
    • 12-15 Volts, 7 Volt Start
    • 0.7 Amp per 1,000 RPM
    • High output with 530 volts and 135mJ of spark energy

Fitting: I mounted the 8x4-inch unit (20x10 mm if you’ve gone metric 😂) on the bulkhead next to the coil.
However, the fixing bolts on the vibration mounts were just not long enough to effectively hold a washer and locking nut, as the engine bulkhead GRP is quite substantial (~7 mm).

So I rivnuted (new word...?) a rivnut to a washer, and used that. This provides enough thread to very effectively spread the load without compromising the GRP💪.

Yes, I could’ve simply rivnuted into the GRP, but I’m not a fan of rivnuting into GRP as it’s analogous to using a cream cracker to spread the load... Iffy, to say the least 🫣

Wiring was straightforward, and the tachometer is now fed directly from the 6AL unit rather than from the -ve on the coil. Cable management took a while, but it had to be neat… Well worth the faffing around. 🤯