Why does my 350 keep burning out the bearings in my altornator?

Are you running the belt too tight?

I have a spring loaded tensioner on the belt so I cannot loosen or tighten it.

You probably can adjust the position of other accessories that would affect the belt tension. Another possibility is that you are buying junk.

I didn't think I could adjust the position of the accessories so i never considered it. I will look into it tomorrow. Thank you

Ok so I'm looking at my engine and I can't adjust the position of any accessories. I just picked up my 5th alternator witch is the exact same as the one I returned, brand new. In terms of quality I can't buy a better one. Unless I go into some rediculous high end performance modle witch would be useless seeing as my engine is stock. Maybe I have been cursed with bad alternators. If my truck requires an altornator with an output of 120 amps but I install an altornator rated for 100 amps (Witch seems to be the one I need), would that burn it out?

Update to my problem. I have a brand new altornator, water pump, and power steering on, all with 10 seconds running time on them. The dam squeling is still there!!!!????? Maybe one of the pully's I pot on is bad? Maybe the main bearing? When the squeling starts my volts drop like the altornator stops charging. No signs of belt slipping. The other accessories are not hooked up to electrical. If the main bearing in the engine was shot would that slow down the altornator enough for the volts on my batterie to drop?

Just thinking. If the main bearing was shot it would slow down the rpm of the engine, in turn slowing down the altornator and all my accessories enough to drop the volts on the batterie?

Absolutely not to the main bearing on the engine... Have you replaced the spring loaded tensioner? To your original question about bearings, have you checked the grounds that are attached to the engine? If an isolated engine/transmission is not fully grounded, this is possible. And one easy way to make sure...run a new ground from frame to engine. Can't hurt.

Ya your right, it's not the main bearing. Yes I have replaced the spring loaded tensioner. Actually no, I haven't checked the grounds attached to the engine from the frame. It is very possible it is not grounded at the moment. Tomorrow I will check all the grounds, and like you said, run a new ground myself to make sure that the connection is not faulty.

If you get it back going, with ground and all, idling...add a little slight, steady force to the tensioner with a pry bar...(yes, I did read that you replaced said item, but I too just went thru this on similar situation with AC idler on Silverado...cheap idler...didn't last 5 minutes, and exploded). If this seem to help, and doesn't seem like too tight a belt...buy a new shorter belt, by a few millimeters...This is easier to do that you think, and it only take 4 to 5 millimeters to make a substantial difference.