350 motor Alternator bracket problems

[SEVENTY1]

About two years ago my father in law and I rebuilt my 350 motor. About 6 months from then, one of the bolts that holds the bracket to the block broke off, actually I think that they both broke off! We were able to remove one, and the other one I had trouble and drilled it out. So the later one I rethreaded the hole to fit a bigger bolt so you would think that it was more support. Well ever since Ive probably put about 1000 miles on the motor with no problems until this past weekend. While I was checking my oil I noticed that the bolt that I had rethreaded and used a bigger size was kinda loose. Well it turns out that with the vibration of the motor the bolt hole is stripped. Has anyone had any problems with this?

Like I said my father in law and I were the ones that rebuilt the engine and put it back into the truck. The only thing that I have holding the alternator to the block is just the one bracket with the two bolts. Did I miss anything, maybe another bracket for support?

Any suggestions are greatly appreciated

[69GMCLonghorn]

At least on my truck, there is an upper and lower alternator bracket. I think that is your problem. Time to head to "ye olde junke yarde" and go parts hopping!

[SEVENTY1]

The one that I have does have the two brackets the lower one and the top one (the one you adjust the alternator with) but they are all held by the two bolts.

[vectorit]

Every time I have seen/heard about alternator bolts breaking or always going loose, is that the bracketry is incorrect for the engine or alternator.

Are you running headers? If so, then the brackets for sure are probably mis aligned and causing undo stress to the bolts.

See if you can snap a few close up pictures of the bracket set up for all of us to see, since there are many different types of bracket set ups out there from GM and aftermarket.

[69GMCLonghorn]

vectorit, you're right about the headers thing, but on mine, everything bolts to the front of the engine block, not to the exhaust.

I'm in agreement, we need some good pics to before we give any more half a**ed advise!

[SEVENTY1]

Ill get pics up tonight! I have no headers the motor is stock. One thing I did notice was that the crankshaft pulley and alternator pulley are a bit off. do yall think that this is causing the problem?

Does anyone have any photos of that area of the engine, I want to see if mine is bolted up correctly.

[michael bustamante]

is your alternator mounted on the passenger side?

[john]

Heres a pic I got from someones build thread. Dont remember who.

[vectorit]

I would bet that lower bracket is for a BBC.

[SEVENTY1]

Originally Posted by john

Heres a pic I got from someones build thread. Dont remember who.

Mine looks just like that with the bracket at the bottom and the bracket at the top. Is there a difference between a bracket for a small block and big block? If you are looking at the engine side was the belt is not aligned perfectly it seems that the pulleys dont align. Its not that off, just a bit. I wonder if this is what is causing my problems.