Originally Posted by
NightFlyer
Are you certain you're getting sufficient current to the distributor? Do you have a spare working coil that you could try?
If fuel, electrical/ignition, and rings all look good, then the only other thing I would suspect is a valve problem. If you have the intake off, might as well take the valve covers off, check for anything obvious (bent or leaky valve), and at the very least have them re-adjusted. After all, gaskets aren't too expensive and you really don't want to drive it until the problem is figured out to avoid risking further/worse damage occurring.
You aren't leaking any kind of fluids from the engine, are you? When running ruff, you're not getting any white or black/blue smoke from the exhaust, right?