Voltage Regulator

[Helmsy]

Is there an easy way (without removing the alternator) to tell if there is a Voltage Regulator built-in to the alternator or if I need an external one?

I have a MSD unit installed and was wondering what effects would occur if there was no regulator installed.

I get radio noise and I have run-on issues and just wondering if it would benefit from an external regulator. Any aftermarket regulators work the same or would it need to be original.