voltage regulator

You still have not answered my question...................just exactly what HAVE you been buying for regulators?

I assume from your statement that you are using the 69/ earlier design?

If this were me, I'd add one more wire and go to the 70 / later design.

To get a better quality 69/ earlier type, buy either an Echlin VR-1001 or Standard VR-128. Either of these is fairly expensve.

But LOTS of guys are using "off the shelf" cheap regulators without failing them.

I agree with a previous post............you probably have a partial short in the field winding.

Hookup your multimeter in the field circuit and eliminate the regulator, that is............

Battery-------multimeter current scale--alternator field--to ground and measure the field current draw.