Need an alternator. Which one?

the battery and fuel pump combo you wish to run in some circumstances must be looked at.
If you are running a lithium battery I know antigravity doesn't want any more alternator capability higher than stock.
Yes, 14.6 max.
If memory serves me correctly I went with the Autozone 140a unit for a '96 impala SS, and I think I swapped the pulley with my original. The Casper's volt booster works great, but it is not a band aid for a failing alternator.
Got the REMY unit. Just installed it. Will go out for a rip and see how it works. Maybe my 80# injectors won’t be at 90% at 23 psi anymore lol
Points to ponder in no particular order:
If you run a higher amp alternator, you need a heavier gauge wire between it and the battery. Probably 2 gauges larger, or more.
Higher amperage causes more voltage drop, anywhere, and this wire has the highest amperage on it, other than the starter.
Larger wire equals less voltage drop.
Hotter ambient temps cause more voltage drop.
There is a different wire size chart for marine wire used in enclosed boat engine compartments, and they calculate that drop on a 30 degree higher temp than ambient. The wire must be a larger gauge.
Your underhood temps will be two to three times that much.
Larger flow injectors usually draw more amps than smaller ones.
Higher RPM causes a higher duty cycle current draw on the injector wiring.
So, build an injector harness with one or two sizes heavier wires.
In your new injector harness, consider the fusible link size feeding it. You need to make that fusible link larger also because of the higher amp draw causes a higher voltage drop in it too.
It also is a good idea to run a larger gauge of wire to the coils, as a higher RPM draws more coil current.
Are you "shotgunning" the alternator amperage/voltage and entire system because there is excessive voltage drop due to too small engine wiring?
Ya know, the first thing you do after turning up the boost, is "hotwire" the fuel pump. Why ignore the ign coils and injectors?
Install a 75 amp or so meter in the battery line feeding the CAR, NOT the starter, start the car, turn on all accessories: hi beam headlites, A/C, fan on hi, interior lites, horns, 4 way emergency flashers, sound system, adjust the power seats, hit the trunk release, open the glove box if lighted, open the trunk if lighted, run the engine at, say 5000 RPM so you have the load from the injectors and ign coils, and have your buddy read the meter.
That's the size alternator you need, plus about 50/75 amps to charge the battery after starting, less with a lithium battery because they don't need, tolerate, or "like" as high of charging rate as a lead acid battery.
You will be surprised at how little the entire draw is for the entire car.
Keep in mind, while driving the car you won't be using ALL of these loads at once. Especially when just "lighting it off" or racing.
I bought the newer Holley "Lite Brite" headlites, they well over double the light output, while requiring much less amp draw (LED) AND, important to me, they are stock appearing!
Food for thought.......
Extremely thought providing and helpful. Sometimes I forget about the different pieces as I am chasing a problem.

Appreciate your guidance!

I ordered an Ac Delco 140 amp for an Impala and now I will test and address the wiring at the same time (even though I am not seeing/feeling a problem).
hello peoples: I got my stock one rebuilt. It works. The place I went to is in Lawrence Mass. I'm sure U have a place in your area.