Alternator keeps burning up

I have a 1989 firebird 350 with TPI. For some reason my 350 keeps eating up alternators. Now I cant get my battery to hold its charge. I am on my thrid alternator. Does anyone have any ideas on what might be causing this?

Are all the ground points in good condition?

you are not going through alternators, you are going through regulators. pretty costly if you keep changing the alternator all the time. if the voltage reads low, than it is 99.9 % the voltage regualtor, which depending upon the model sits inside or outside the alternator. you only need to replace the whole alternator if the bearings are bad, but even then you can still change those. also if you have a really old alternator the charcoal contacts might be gone and you won't get a charge either. but if you keep replacing a new alternator with a new alternator, then you keep burning up the regulator. check and make sure that all connections to the alternator are correct and where they need to be. also check for a short.

Check the overall condition of your battery as well. As batteries age they require more and more charging, which puts a greater load on your alternator and regulator. A bad battery will quickly fry an alternator and/or regulator.