I bought a running wrecked Z28. But due to an injury it took me months to get ready to pull the engine. I had been starting the car every week or so and even driving it a bit. The week I decided to pull it in into the garage it wouldn't start, figures. Diagnostics said opti, as it turned out it was the ignition module and the coil wire. The opti could have also been bad, but I didn't put the old one back on to test it. The old setup was MSD, I've never been a fan of MSD. The cap and rotor needed replaced anyway so I'm sticking with the stock GM part.
You don't have to pull the hub, you do have to pull the balancer and everything else on the front of the engine, what a PITA. What were the GM engineers thinking?. The balancer clears everything with plenty to spare.