Thanks. So just goes on top and screw in?Holds the plug wires down
Yes. It's not necessary though.
If you're currently shopping for ignition stuff, I'd recommend staying away from MSD. I'm currently fighting with an MSD system on a customer's car that was installed by his brother, and it's had multiple part failures in less than a few hundred miles. Much of what they sell is made in China, and it just doesn't seem to hold up very well.
Jeff
Google MSD plug wires