Alt replacement

The headlamp relays help since they keep those currents within the engine bay. Your headlamp switch now simply controls the small currents (~50 mA) to actuate the relay coils.

The higher output alternator might only exacerbate overloads, so more important to insure your wiring is primo. Especially check for corrosion in the bulkhead connector. It is common for the large current on the ALT and BAT terminals to melt the plastic if any corrosion (resistance = heat). That is why Mopar did the "fleet bypass" on Police and Taxis and people here similarly do the "MAD Bypass".