c.;

Clearly there is something not right with your setup...and since you did not experience a noticable improvement after you upgraded, I suggest that there was a pre-existing problem which your upgrade did NOT correct (like fuseblock corrosion, poor connections etc. ...), an additional problem has now occured (like battery or alt. failure etc.)...

I do have to state that (quality rebuilt) Delco alternators are highly reliable, and an alt upgrade, when succesfully performed and with everything right and working properly, typically results in a NOTICABLE improvement over the oe genny system (with good stiff system voltage, and charging starting just off idle, as opposed to higher RPMs in a genny system)...ask anybody around here, a SwEm upgrade vintage Volvo is (electrically) "brick reliable" again [end of plug!]!

That voltmeter, is telling you something...BUT, it depends where it is connected...if across the battery and reading low, your bat is either discharged (so you're not charging...duh) or bat itself has a problem...if connected elsewhere, you need to tell us where, so that we can better help troubleshoot...

Suggested reading: Gas-Tight-Joint and Electrical Ramblings at: http://www.intelab.com/swem/techarticles.htm

cheers