When I rewired my engine compartment I deleted the ballast resistor and replaced the coil with an MSD High Vibration coil which allowed me to mount it on it's side in the same location as the one it replaced. I mounted the GM HEI module to an aluminum heat sink with thermal paste using one of the mounting bolts for the coil bracket.
So far I have had no issues with this setup using a GM 1-wire alternator which is internally regulated.