After 4 years Now she just won't start

Mike you don't necessarily need to go to the new style regulator, and of course you need the 70/ later isolated field alternator (often incorrectly called "dual field.) You can also use a Standard Motor Products VR-128 in place of your '60's regulator.

One problem with OVER charging is voltage drop in the ignition harness. Easy to check----

Turn key on, engine off. Put a meter on the battery positive post, the other probe on your IGN terminal on the regulator. You are hoping for a VERY low reading, lower than .2--.3V (2 TENTHS of a volt.) IF higher, you are "losing voltage." Your top suspects are the bulkhead connector, connector on the IGN switch, or the switch itself.

Next, check the ground integrity. To do that, start the engine on fast idle, put one probe on battery NEG and the other on the regulator mount frame. Be sure to stab through any rust, chrome, etc.

Again, you are hoping for a very low reading. Over .2V means the block/ body/ battery/ regulator are not truely grounded.

Last, with the battery "normalized" and the engine and regulator warm.,, check battery voltage right at the battery on a fast idle. Optimum is 13.8--14.2, allowable is 13.5--14.5. Anything over/ under means some amount of trouble.