Alternator Pulleys

[Griffer]

Onother question for early car owners,since owning my 4.0ltr when first started the alternator light stays on unless I rev up to kick the regulator in,no charging problems, just an irritation. An independent at the last service reckoned that my car is fitted with a smaller diameter pulley,this would explain it as at fast idle the unit would be rotating slower than if fitted with a larger pulley, it measures at 82mm OD or 3 1/4" in old money, if this is so, what should it be, there is bags of adjustment left on the alternator adjuster bar. Thanks guys .