This is a reminder to those with forced induction engines.
Some of you probably noticed the DSII distributor in one of my engines pics. I originally had DSII with an MSD6T with a two-step and 3 pre-set retard switches. The switches were connected to retard ignition timing at each gear change. The thought was the longer and harder the engine was under load, more timing should be pulled.
I had nothing but trouble - low 11's was as fast as the car would go - and hurting parts. The more electronic stuff I disconnected, the faster the car went. I went back to my original NA distributor, Mallory 3 lobe cam dual point. Went 9's. I couldn't figure out why the two-step wouldn't work, never slowed the engine down.
Turns out MSD's are sensitive to electro magnetic interference, as most electronic equipment is. Spark plug wires must be the best spiral core you can get. Also, all wires to your magnetic pick up need to be separated from other wires. They now have a shielded cable for this.
What was happening was the ignition was firing randomly from the false signals. On a NA engine it would probably go unnoticed, kinda like a wasted spark system, but under boost you could have conditions favorable to ignite the air/fuel mixture far enough advanced to damage engine parts.
I plan on going back and trying it again with the new build. There's a definate advantage to use a two-step on a clutch car to launch under boost.
With a Mallory extended dwell dual point, I was also able to start my tripower without choke by pumping the throttle a few times in Michigan cold winters.