Dan,
A number of benefits, but to get the most out of the system, you should use a more efficient E core coil such as a MSD 8207 or Summit 850500. These are stand alone coils. If you get a HEI dist, it of course has the coil-in-cap.
Because of the higher energy output, you can run 0.060" plug gaps. Another thing HEI has is adaptive dwell. It reduces dwell [ coil on time ] at lower rpms because it is not needed. This reduces coil heating which wastes energy. At higher rpms, dwell is extended to reduce misfire.
If you elect to use the HEI dist, you also clean up the engine bay because everything reqd for ign is in the dist. Also available from MSD & Summit are upgraded HEI modules that have adjustable rev limiters, if that is needed.
