[Hozer 88GTConv]

Jester: "Powermaster alts are "1 wire" type, correct? If so, where does that "1" wire connect to? I belive you said the starter solenoid, right? Check for corrosion on ALL the terminals on that solenoid post. Also, no washers between wire connections on there either. Galvanzed washers make good insulators...."

Powermaster one wire hookups go directly to the positive terminal on the battery.
Do you have the two blade terminal hookup for the voltage regulator on your powermaster too? I have the stock green wire going to the upper blade terminal as recommended by powermaster. Nothing is conncted to the lower blade terminal.
I don't want to sound redundant, but was the diameter of the pulley on the alternator ever measured?
I had this problem forever, b/c I switched alternators after I had installed underdrives, so my old alternator had the underdrive pulley, Not the 140 pwermaster out of the box.
I have 14.4volts at idle with a 1 7/8" alt pulley.
my grounds are crappy too, I still have that worthless stock strap from the head to the firewall and nothing going to the frame.
this one is going to be good...