Voltage regulator
 

I purchased a Delco-Remy voltage regulator from Ames. After I installed it, the voltmeter read a little over 14 volts. After a minute, or two, the voltmeter started fluctuating between 13 and 14 volts, and the headlights were flickering. I will admit that I don't know much about external voltage regulators. My question is: Is there any way to adjust the regulator to eliminate the voltage fluctuation, and keep the headlights from flickering? Car is a 65 GTO with 10DN alternator. Any help appreciated. Thank you.

Which version did you purchase? The M239 & M239BD looks mechanical and may be adjustable. The M239SS is electronic and non-adjustable.
Replacement mechanical regulators (probably a rebranded Transpo) have a different design than the originals and I've never seen an instruction sheet for them. I found their voltage regulation has wider range and a little more difficult to fine tune.

When your voltage is fluctuating, do you hear a buzzing sound coming from the regulator? If so, it definitely need adjustment.

What was the reason for buying a new regulator? First suspect would be a grounding problem. Make sure grounds to engine and body are good, and make sure the regulator is grounded.

Regulator is a M239. Internally it doesn't resemble what's shown in the service manual. In the service manual it specifies point gap and air gap. Where are these measurements taken and how do you adjust them if needed? All grounds are good, and regulator is properly grounded.

You probably have a design similar to these photos. The hex screw holding the center points plate in front of the regulator coil functions like the nylon nut on the original. The spring tension is adjusted by bending the metal in the rear of the regulator coil and replaces the original's philips screw. If you keep that in mind, you can follow the instruction in bulletin IR-262.

Mechanical units are not the best , use the electronic one & be done , send PM if in need , i have some Wells units avail .

Agree- Is it possible the flicker is pointing to more than voltage fluctuating between 13 and 14 volts?

After numerous adjustments to the regulator, I could not adjust out the voltage fluctuations. I bit the bullet and installed an electronic regulator. Problem solved. Steady 14 volts at operating temperature and RPM range. This is with head lights on high beam and blower motor on high. All is good. Thanks to all for the advice and help.