My 720 gas. Having never been able to diagnose the generator/regulator problem, I gave up. I have junked a great many early Pontiacs, several with internal regulators in their alternators. Had 6 tested, one failed. I made up a bracket using the original one as a pattern, used the original adjusting strap & belt. Looks like factory!!! When I went to hook up the battery wire, I got what looked like striking a welding arc. Dawned on me I had to change the battery over to negative ground. The existing battery cable was too short for the battery I had just bought.. It has a couple taped places in it too. Installed a small diameter welding lead that is 2ft longer. The battery end is an auto parts universal in a larger size to accommodate the larger than automotive cable.
Now.........I have also assumed that I must switch the coil terminals.........???? And the amp meter connections......??? Am I missing anything???