When I researched that long ago, the AC version alternator for 73 Datsun was larger diameter. I read somewhere that this wouldn't fit so I measured where it would go, and concluded it could be solid against the block and the existing adjustment strap still wouldn't reach out far enough.
It sounds like today's alternator has 35 amps in what used to be a 25 amp shell.
But unless you are night plowing or moving snow, I don't see a need for more amps. Especially with the LED bulbs used now. The original 15 amps is sufficient to just maintain the battery for starting - for daylight work.
