My 1985 Dodge W250 is overcharging It does not have the firewall mounted vltage regulator has a 114 amp heavy duty alternator Is be self regulating or somewhere else?

The 1985 Dodge W250 does not have an external voltage regulator but does have an internal voltage regulator inside the alternator itself. If your truck is overcharging its likely your internal voltage regulator has gone bad and will need to replace the alternator in order to correct this. This is a common failure point on older vehicles.