I created this diagram to show how to hook up the headlights to run off of relays. This has a couple of benefits:

1) It allows for the use of higher output headlights
2) It reduces the strain on the dimmer switch, headlight switch, and main harness.
3) Your existing headlights will be brighter as the wire path will be shorter.

This diagram is for 12v negative ground cars, but it could be easy to adapt for any car. On the postwar Packards you can hook it up using the junction block at the driver's side fender so it doesnt require any cuts to the factory harness.

Please use a waterproof fuse holder on the feed line from the Starter Lug, and also use waterproof relay holders. Also the feed line should be 10 or at least 12 gauge and use relays rated for the amp rating of the high beams.

Enjoy!