You need one of these

[bumpster]

I know a lot of you need high amp alternators for winches, stereos, and such, so upgrading to an internal alt is the way to go. On my 72, all I needed was for the lights to stop going bright, then dim, then somewhere in between. I installed an electronic voltage reg from whitney, (item AJQ737135R), simply because it was cheap(10 bucks), and I didn't have any more late style alts. laying around. This thing works good, looks and installs just like the factory setup, and made a huge difference. Now alt kicks in at about 400rpm and no more power surges. If you want to keep showroom looks this would be a good route.