Need Opinions on Alternator

The alternator rating is only a manufacturer's claim -usually an approximation of maximum output (which only occurs at high alternator rpms). Sometimes a higher output alternator will do better at low rpm as well, other times they will do worse. It depends on how the extra output was achieved.

In any event, when all is working well, the alternator only puts out current based on demand.
The danger of overloading the wiring is when there is a bad connection (which will get hot), wires grounding out, or extra loads. Lets say for example the battery is dead and the car gets a jump start. Then its driven at highway speeds. Potentially your new alternator could put 90 amps through the ammeter as it tries to recharge the battery. Thats more current (flow) than the ammeter and wiring was meant to handle, never mind possibly deteriatoriated.

The a-body headlight wiring is particularly weak. They used the absolute minimum wire size needed. For that alone, please consider a relay system. You can buy them premade. I've personally had headlight circuit breaker flicking off on the highway, and in another a-body the connector to the headlight switch start to melt.