I have a 65 Fastback with the 289. I've recently purchased a 100AMP 1-wire alternator to replace a 60A 5 wire alternator but can't get it to work. When I install it my Voltage gage reads just under 12volts(battery) which tells me that it's not working. When I have the 5 wire alternator installed the guage will read 13 to 14 volts as it should. I've taken the 1 wire amp to my local Pep Boys and they put it on some kind of Alternator Tester Machine which came back with positive results. Every test they ran on it passed so I installed it again but got the same results as last time. The belt is tight, I'm connecting the wire up to the positive terminal on the battery. Does the alternator need to be grounded somehow? My block looks to be grounded? Any help would be greatly appreicated! Thanks