Not Charging

[slamons]

71 390, replaced the Alt. and voltage reg. still running off battery only, after a few hours battery is dead. Battery will not charge while truck is running. Any suggestions? wiring is in good shape, Not getting a reading at the gauge either...

[FORDification]

Check out this link:

http://www.fordification.com/charging.htm

Have you done anything electrical to the truck lately?

[Thunderfoot]

The 71 will have a fusible link on the main power wire between the alternator and the starter solenoid it could be bad... To check it you can either ohm it out or check the output terminal on the back of the alternator for 12V power. You can check for this power without the motor running as it's connected to the 12V power at the solenoid.