Years ago I had an msd 6a and it used to shut off when hot. That was 25 years ago. I currently have an msd 7AL on my race car. It has more capability than I need. It has not gone any faster with the msd. I did run into a problem as it is finicky about battery voltage. I had to add an alternator onto the car to make it run clean. Street car this is not an issue. It has features such as start retard and I can set it up to retard timing if I ever run nitrous. For my basic slow set up benefits are minimal. I running a factory style electronic distributor fired by an msd blaster coil.
