I use an MSD 6A box and distributor. Couple of things to be aware of. First if Your car has a tach, you'll need a tach adapter (MSD #6910 for duraspark distributor, 6920 for MSD distributor). Also, after installing mine, my alternator wasn't able to keep up anymore. I don't think it draws a lot more power so much as my alternator was probably marginal to start with. So if your electrical system is maxed out or marginal than that is something to keep in mind, though that doesn't seem to be an issue for most folks who install it.