Is my sparky lying, please help?
 

My battery has been over charging lately. I took it to a sparky who said "the alternator had damaged the regulator" and that if I just replaced the regulator the alt. would just damage the reg. again.

I think he said something about a stuffed diode?? in that particlar alternator.

Is that vaguely correct or is this guy taking me for a ride?

I have an 86 5.0L engine (the engine was originally out of a Taxi I think) that has a big-*** Motorcraft alternator with external regualtor.