I have the Volvo MD17C, from 1977.
I can recommend highly the 100 A "small frame" alternator from the American-supplied Ample Power together with their (separate) 3-step regulator. I bought that set-up in 1992, and it's still going strong. It is, apparently, capable of 100 A continuous output when the temperature is 93 degC. I trust that is the air temperature. That is very hot indeed. Even in the tropics, your engine room, properly ventilated, will not reach that. Here in Scotland, I always leave the engine room wooden panels off the motor, such that the engine an alternator breathe cold.
Jt, everything hinges on the "continuous output" rating. I bought a rival's 100 A alternator. It lasted one half of an afternoon. I kid you not.
The Ample is not cheap, but it just keeps rolling....
Ample Power Alternators
.... I think mine is the 4023.
Of all things, at heavy alternator loadings, spin the engine fast. Keep those revs up. The big centrifugal fan on the front of the alternator must be kept spinning fast. The alternator cooling thrives on revs. Cooling is everything to the alternator. When you first begin a re-charge, rev the motor and hold the revs up until the charge current drops off. When it drops off, you can drop your revs a bit, and given time, you can drop to idle again if you wish.
I have no other interest in Ample Power.