[JCoop]

I've heard of MSD units failing within the first 30 milnutes of use. An article about small block tune in the last Second Strike newsletter talks about that too. I thought about changing the Accuspark unit in my SPF Cobra so I could have a rev limiter. Then, Pertronix came out with a digital rev limiter that you could add on, so I bought that. The Accuspark is extremely reliable, idles the 460 down to 600 RPM, and will rev that sucker without a miss up to 6000. (Well, that's where I set the limiter).
If you're starting from scratch, mybe the MSD distributor, 6AL ignition, and blaster coil would be a consideration.