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For sale is a complete Marelli Plex electronic ignition system.This comes with three HEI modules including a new, in the box, ACCEL, unit.
The system needs a new pick-up line that was shorting out. The distributor model is SM804AX.

Asking $100 OBO.
 

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The only downside was the long advance curve which suited emissions compliance more than performance, I had a couple of them with modified advance mechanisms that worked quite well. Richard Jemison uses the distributors to fire Crane spark boxes on his race cars.
 

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Papajam told me the advance could be changed with springs from a Moroso 72300 kit. I never got the instructions from him. I know it entailed filing something on the distributor and swapping out one or more of the springs with springs from the kit.

 

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One of the canned advance curves in non-communicating 123 distributers is Shankle's modified Plex curve.
 

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Papajam told me the advance could be changed with springs from a Moroso 72300 kit. I never got the instructions from him. I know it entailed filing something on the distributor and swapping out one or more of the springs with springs from the kit.
Just about any light advance spring will work. When the aftermarket 'Plexes came out there was an article in the Owner that recommended the secondary spring from a Hemi 4 barrel carb. I'm still using that setup on my 2 liter Super. (There's photo of it on the "Marelli Plex Photo" thread.) Making this change will give you full advance at about 3k or so. This is what I'm running now. We set the max advance at 36 degrees and my modified 2 liter (Centerline 11.1 intake cam, 10.1 more or less Motronics, headers, etc.) runs exceptionally well. MSD sells a pigtail adapter that makes the 'Plex plug compatible with a MDS6A. I'm not running that now, although I have i the past. The 'Plex and the MSD make for a great analog ignition.
 
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