please if you still are using the ammeter, don't connect it to the batt, but to the alt stud, to get a correct ammeter reading and don't get stressed the ammeter unnecesarilly with a load wouldn't need to read.
Even if not using the ammeter, it is still often better to connect the relays to the alternator. Way too many people bypass the ammeter thinking all current flows through it (which of course is not correct).
Hooking to the battery on a 'typical' mopar system, with or without the ammeter, doesn't change the fact that the power to the headlight relay will still flow from the alternator through the bulkhead connection, to the mains splice back to another connection on the firewall, through a fusible link to another connection, then finally to the connection to the headlight power relay.
I put 'typical' in quotes because his '76 D300 may have a different arrangement for the power feeds. I don't think so, but I don't know for sure.
