There several reasons why the 123 is superior.

First the other systems of electronic ignition (Crane or Pertronix) require that the original mechanical centrifugal advance system be still fitted which suffers uneven wear and consequent lumpy running of the engine because each cylinder has its own inaccurate ignition timing. Furthermore they all require a separate box for the associated electronics.

The 123 ignition is different, all is contained in one simple module which just goes in place of the original points box, the points operating cam is removed along with the advance weights and their bearings which wear, two strong, small magnets slip onto the drive pins which previously held the advance weights.

The most important advantages of the 123 ignition system is simple to installation without mechanical adaptations.
It has a smoother engine torque curve.
No maintenance – ever again!
Variable dwell angle to prevent low speed overheating of ignition coil and make a better spark at all speeds.
Better starting.
Better emissions.
Better fuel consumption.
Built in LED for simple static ignition timing.

I used a Crane and it failed after one year. The 123 is designed to last substantially longer.
My 68' 280se coupe has run very well since I installed the 123.
I believe any 40 year plus old auto should switch to this system.

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Britton McIntyre

68 280 SE coupe 'Hairball'
70 280 SL
71 280 SEL - RIP May 2010