Best coil, box , resister combo ?
airgrabber,
One guy here said he has seen failures of the Mopar HEI ready-to-run distributors. Skip White Performance in TN sells many of them, and is a race shop, so they would have the best info on failures. Whether they would be forthcoming is another story.
Many here use a Mopar electronic distributor to trigger a GM HEI module. That might be more robust, and you can use the better 8-pin HEI module - simple connection to GM coil, ability to computer-control timing.