This suggests that the alternators are wired in simple parallel, on all terminals, but I'm not sure about the way it shows the output cables BOTH going to the LEFT battery. The single (RIGHT) alternator is actually wired to a fusible link going to the top of the starter cable (because they're assembled onto the engine before the body is lowered onto the chassis) on the RIGHT battery.

The dual-alternator belt is 6 ribs 120.3" long; at
O'Reilly, a
Gates Micro-V AT K061203 is ~$52.
________________________________________________________________
These units feature a high ampere output-to-weight ratio. The Delcotron CS-130 & CS-144 alternators are electrically similar to standard units, however, they do not contain a diode trio. The voltage setting of the integral regulator varies with temperature and limits system voltage by controlling rotor field current.
The regulator has four terminals; "P," "L," "I," and "S."
The "P" terminal is not used, except as a tachometer output for diesel engines.
The "L" terminal may be connected to the instrument cluster for charging indicator and voltmeter.
The "I" terminal provides a voltage feed for the heated oxygen sensor, variable throttle control relay, and electronic automatic transmission.
The "S" terminal is not used.
It uses pigtail
PT1235.
The alternator is serviceable only by complete replacement only. No periodic maintenance is required. It should not be disassembled for any reason.
The Generator provides Voltage to operate the Vehicle's Electrical System and to charge its Battery. A magnetic field is created when current flows through the Rotor. This field rotates as the Rotor is driven by the engine, creating an AC Voltage in the Stator windings. The AC Voltage is converted to DC by the rectifier bridge and is supplied to the Electrical System at the Battery Terminal.
This Generator's Regulator uses digital techniques to supply the Rotor current and thereby controlling the output Voltage. The Rotor current is proportional to the width of the electrical pulses supplied to it by the Regulator. When the Ignition Switch is placed in RUN, narrow width pulses are supplied to the Rotor, creating a weak magnetic field. When the Engine is started, the Regulator senses Generator rotation by detecting AC Voltage at the Stator through an internal wire. Once the Engine is running, the Regulator varies the field current by controlling the pulse width. This regulates the Generator output Voltage for proper Battery charging and Electrical System operation.
The Digital Regulator controls the BAT Indicator lamp with a solid-state lamp driver. The Lamp Driver turns on the lamp whenever Undervoltage, Overvoltage or a stopped Generator is detected.
Voltage is available to the indicator lamp and the Generator when the Ignition Switch is in RUN," Bulb Test or "START." The 20 Amp GAUGES Fuse 4 located in the I/P Fuse Block provides voltage through the PNK (39) wire to Instrument Cluster PIN 22. When there is no current flowing, Battery Voltage is available at PIN 19 and is provided the Generator through the BRN (25) wire. Generator Connector Cavity B connects to Generator PIN L. This Voltage input provides operating power for the Regulator when the Engine is running and Generator Voltage is too high or too low, this Voltage input is grounded by contacts within the Regulator. This Switch closure allows current to flow which causes the Charge Warning indicator to light.
For Vehicles with the Diesel Engine, the Tachometer input is sensed at PIN P of the Generator. Generator Connector Cavity A connects to Generator PIN P to send the pulsing Voltage signal to PIN 6 of the Instrument Cluster through the WHT (121) wire. The Instrument Cluster converts the Voltage frequency to Engine RPM.