FWIW: 120A tops 130A I believe is the MAX a single 13A belt can safely drive too.
I managed to score a pimped up GQTD42 180A jobbie years ago for my 6.5 GU.
Initially it cooked the diodes under stress until @
PeeBee kindly ordered me in an external rectifier pack from the States. That fixed the cooking issue no problem but unfortunately the next problem became belt slippage under heavy loads duress.
The Evil Twin Legend on here kindly posted up a graph somewhere years ago helping us which listed the required belt/s V & Serpentine variants required for higher output alternators

Sent from my iPhone using Tapatalk