Alternator gauge bouncing

[Remusa12]

I've got a 73 charger that I swapped a big block into it has a new battery and a new alternator.
My problem is it wasn't charging before and I figured the factory gauge just didn't work but it died while driving a few times. I've played with the box on my firewall and then it started bouncing between all the way right and just in the middle it's never gone left into discharge except for maybe its a little more left middle.
When I turn my electric fans on it goes all the way right and turning on lights and pushing the brakes makes it go between the middle and right. After the car warmed up sitting in the driveway it seemed like the charging was all the way right. I don't know if any thing is normal or its not good.

 

[moes]

the box on the firewall, are you talking about the bulkhead connectors? If so take it apart and clean all the connectors both sides and pack with dielectric grease to seal out the moisture. It sounds like you have some bad connections.

 

[Remusa12]

I believe it's the regulator it's the box on the firewall with the big plug beside the electronic ignition box

 

[moes]

check this out, it should help you