I'm setting up a Pertronics HP for use with a 123 Distributor and need to determine if the 123 Distributor is rising edge or falling edge. Points and electronic are listed as rising edge, and magnetic is falling edge. Hoping for a quick answer here before making the phone call. This is for a warmed over Carrera 3.0.
Thanks

I wish I could help but I am drawing a blank as to what you are asking and for that matter I am not sure why it matters? I do run a 123 dizzy in my 2.4-6 so I have some experience.

When I fitted a 123 to my car, a 2.7RS spec 6, I got rid of my MSD 6AL altogether.

That said, from what I've read, even though the 123 has its own electronic ignition you can run a separate stand alone ignition box with it.

Is there a reason you don't want to run the 123 on its own?

Here's the CDI I will try:

https://pertronixbrands.com/products/digita...anodized-finish

So I tried just the 123 Distributor coonected to their recommended coil, and the engine runs great from about 3000 RPM and up. Problem is big Mod S cams, PMO 46, and 1 5/8 headers. Before I tackle carb settings, I want to ensure idle and low RPM spark is as good as I can get it. One of the Pertronix CDI settings is rising or falling edge input.

I built an RS spec with Weber 40 engine in the mid 90's. Best one I built. But that had smaller bore, smaller carbs, less cam overlap, and smaller headers. It also had the Porsche CDI. So no doubt I need CDI on this engine.

When working on my 930 I was working with a CDI rebuilder to troubleshoot a no start ignition issue. Somewhere in the convo he told me the CDI used rising edge signal to control spark. He showed me a graph comparing the two. I recall the rising edge was stronger and more precise with less noise.