I have a '68 Chev with an altenater and external regulater which is mounted on the radiator support. There are three rubber inserts that go through the support and three small screws that draw the insulaters up totally isolating the regulator from the rest of the truck. THEN there's this small black wire that deliberately and positively grounds the regulator to the very same radiator support!

Why is this??:confused:

the rubber isolates the vibrations... think of them as shock absorbers.

Thanx Longhorn, that's the only thing I could think of, but as snug as the inserts were I didn't think there was much "anti-shock" value.