Evening group, 1986 IROC-Z, 305 TPI, 700R4.
Driving my car last weekend and glanced at the instrument voltmeter gauge and it read under 8 volts. Changed the alternator with a remanufactured alternator (108AMP). Bench checked replacement alternator, at 14 V output.
For a safe measure, changed battery out with a Duralast Gold. Got it checked out at O'Reilly's while running and the battery stored 12 V.
He checked the starter volts and they were in parameters.
Heard stories that if you put a new battery and alternator in it'll read low until the voltage regulator identifies a need to charge. Sounds like an old wife's tale.
My car usually read around 13-14 Volts. I cleaned the ground cable and checked for a loose starter cable...it's tight. Ran the motor and turned on the parking lights and they might as well be candle lights on a old horse and carriage. What am I missing here?

 

I don't know if this matters, but I completely detailed the engine bay for an up-coming car show. Cleaned and repainted the block, wiped down all the harness covers and dusted everything with bull-dog to give it a nice sheen.

 

You should post in the electronics section not the programing section
you will get a better responce