Thinking of changing to 1 2 3 for the mk2 . Opinions please . Is it a simple changeover .
Simple question…… why
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That’s the purpose of my thread , do determine the pro’s and cons and find out a little more about it .
Why? Well it gets rid of the sometimes troublesome condensor. It slso gives a bigger spark, more stable timing, less scattered. It does not make your ignition system maintenance free but it does get 90% of the way there. I’ve fitted about 10 of them with excellent results.
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I have 123 ignition on all my 4 classic jaguars.
On two of my cars the original ignition was warn so bad that they were unusable.
Easy to adjust, and you never have to look at it again.
I like them a lot, that why I also changed the other 2 cars.
Isn’t Megajolt / EDIS combo a better option ?
I had a decent distributor, so fitted a Pertronix unit with matching coil. I really like it. Starts immediately and runs smooth. It cost much less than a new 123 distributor. Those are nice, but too rich for me. Plus if the Pertronix unit fails, just put points in and carry on.
Changing from the original to a 123 for me made the engine run much stronger, faster start and pull harder, especially as I could tweak the advance and give it a lot of advance from 1000-2500. Then switched to EDIS, and the engine is even MORE consistent. Starts immediately and runs very smoothly. The downside of EDIS is there’s a single mapped curve vs. the curve + vacuum advance. Car runs better overall but it could use professional tweaking which I just haven’t done yet.
I installed a pertronix unit about 10 years ago and haven’t looked at it since.
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I guess the “why” has been answered!
Unanimous verdict I think , thanks guys . Oh , one more thing , I put on a flamethrower coil from Distributor Doctor , is that ok , or will it need changing ?
Any decent coil will work, and on a non-super/turbocharged engine, hi-output coils make little to no difference.
Wow , saving money already 
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Hi Ken,
I put the 123 ignition with a new coil and new ignition wires into the 7m.
In combination with refreshed carbs a very good invest.
I also changed the manuel choke back to the solenoid.
The engine runs very good.
Best regards
Wolfgang
Uhm, the Megajolt + EDIS has a full 3D map with vacuum.
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Uhm, I know I installed and programmed it. My point is it reacts to total manifold vacuum vs. a distributor which has ported vacuum which triggers the advance (for example on the highway). Different systems.
Agh ! , Seems it’s for the big cats only , can’t find one for the 2.4 
That is the one that I have, I have the negative earth type ( converted my MK1 )
Price looks Ok for this version.
That looks great , who is the manufacturer , phone , E mail ? Please .