Re: 1965 Galaxie alternator question????????
if you have screw on cover on the regulator, you can take the cover off and check it out- with the engine running the single contact relay should be 'on' to activate the field, and the other double set of contacts adjusts the field current. with a voltmeter on the battery(and at least low fan or some lights on to pull a little current), if you press on the double contact, voltage should drop(low/trickle current), if you pull it between the two contacts voltage should increase (mid current), and if you pull it to the top contact, voltage should really go up(max current).
Note the relay contacts and frame around them are NOT AT GROUND, so keep metal away, and use only light pressure on the double contacts- the spring tension sets voltage cutoff level, you probably wont want to change that.
If three steps in the current arent seen, one of the little wirewound resistors on the bottomside of the regulator might be bad- if only the 'max' current is working, it might not start charging until battery is really really low, then it may cutout at the midpoint- before battery is fully charged.
If it aint the regulator, you might want to just unplug the cables at the base of the cowl that plug thru the firewall into the back of the fuseblock- if any are corroded(it is 40 yrs old) a bad field power or ground may be screwing things up intermittently. Bad grounds can do weird things, you might want to just remove any grounding ring terminals you can find, clean off any rust, put some new screws in any that look questionable. A bad ground in my lincoln was messing up my dash lights, but also burned the fuel level sending unit up-wirewound portion was burnt in half inside the tank...lucky there isnt much air in there!
Confidence: that feeling you have just before you realize the mess you've gotten yourself into...