10SI voltage regulator fails repeatedly
I install a new (NAPA rebuilt) alternator and all is well for anywhere from a few minutes to a few months. This last time it was just a few minutes. Start the engine after the install and all is well. Hit the road and after a few minutes I can watch in frustration as the ammeter begins it slow climb until it's pegged. It took maybe 3-5 minutes to peg. On other occasions this would happen and then repair itself but in the long run it got to the point that the ammeter was continually pegged. It's in an L98 in a 58 Vette that doesn't have A/C or much of anything other than electric fans. I don't see any evidence of the battery boiling and there are no codes being thrown. Output voltage at these times is 15-15,2 volts. IDEAS PLEASE!!!