I have a few observations I wanted to post. Hopefully they will hope someone.
I have a /6 2.7l high compression. It is a fresh rebuild. I had a MSD 6al however it wasnt working. The price on the street fire CDI units was appealing. First observation is that it is considerably smaller than the 6al. Second is that it has built in rev limiter adjustment- which MY 6al did not have.
I have a pertronix ignitor, flame thrower coil. I hooked them up without the MSD and use an ignition spark tester (two electrodes- one ground, one to spark plug wire). You can adjust the length between the electrodes so I set them about 2mm apart. When I cranked the engine, I could see a very faint spark about the size of a thread.
I then tried the same test however with the street fire CDI hooked up. I just saw a bright flash on the ignition tester. I then separated the electrodes 5 cm (50mm). I cranked the engine and there was a wide bright repetitive spark (looked more like a flame).
The car seems to idle much better. I haven't got to drive it yet so I will have to give a further report later.
Conclusion- the visible spark was considerably larger and longer lasting. How that affects the engine- TBD.