Ol'Reggie wrote:
It seems clear that the alternator is not the problem - 2 new alternators charging at 12 volts?
It seems pretty clear to me that just the opposite is true: That the alternator IS the problem.......unless the new battery has a major fault, like a shorted cell or an open internal connection.
The other possibility is that none of these mechanics realizes that on a model that old, the REGULATOR might be a different unit and not a part of the alternator like is always true now.
If there is an electric motor shop in your area they should be able to sort this out quickly.
Most modern automotive "mechanics" don't know beans about electricity.