Chieftain, the alternator i installed has TWO and ONLY TWO terminals as did the one I took off. AND, there were no "extra" wires hanging idly by with nowhere to go.
The presence of a case ground seems to be spotty - and its utility is somewhat equivocal anyhow.
I know that the Delco CS130 used in RENIX has provision for a case ground, but it was never supplied from the factory. It has, however, fixed "floating voltage" issues that have cropped up (principally because the primary engine ground is back by the dipstick, and the alternator grounds through the case and mount.)
I won't say it's absolutely necessary - but it can be helpful. The primary reason that Delcos have long had a case ground provision is simple - the most common alternator in use in conversions, kit cars, and customs (and quite a bit of industrial equipment, for that matter...) happen to be Delco SI or CS series. Delco noted that shortly after the SI series came out, and the drilled/tapped hole in the boss in the back of the case was added.
Very early SI units don't have it - but it's pretty rare, since most of them have been replaced anyhow. The CS series (CS121, CS130, CS144) have
always had provision for the case ground.
In the event that a ground would help but there is no provision for it, simply use one of the mounting screws to attach it. Same net result.
