How can I test an alternator?

[TooLoud4You 0]

Hi someone locally is selling a 300amp alternator for my car, which is a 2003 4.0L Explorer.

I know the guy and he said he never used it because he just sold his explorer but he bought it from

a place in cali. What should I be looking for to see if the alternator is legit? what tests can I do?

Or should I just get a 240amp iraggi alternator?

Any input would be greatly appreciated

Thanks!!

[jonbearsmt 919]

auto zone can test alts.. but they dont go up to 220 amps... they max out at 130...

so you would have to find a custom shop that has a amp clamp. and then install it on something.