The one I posted is cheaper...

But at least you get the idea now.

Also, if it is low rpm (idle)related, then the smaller alternator pulley will probably help. If it's all the time, it is likely something else.

 

No its onlt when the fans kick on. What size belt do I need? Is it 90mm? Would it be the same as a fbody? thanks

 

I don't know about the belt length. But it's going to need to be shorter than stock for sure. I'd wrap a string around all the pulleys to get a starting point for length.

Try the pulley first. If that doesn't take care of it, then you may need to step up to a higher output alternator.

 

Well the only change from factory is the pulley. So hopefully the alt. Pulley will counter it.