Headlight / engine wiring issues
1966-74 A B E-Body Engine Forward Light Harness 1974 A Body V8 Built Before October 12
Is this something like what I'd be looking for? There's so many I'm unsure. It's a 74 dart sport
We're not going to know the specifics any better than you.
You may be able to estimate the build date from the VIN
The VIN will indicate which plant the car was made and sequence number.
See if your car still has a fender tag. Fender tags and build sheets have a lot more info on it. There's some folks here who can help you decode the options and what the dates represent.
Failing that you will have to figure out what change occured to the harness. Year One or M & H ought to know since they are the ones offering it.
Save your old harness. There may be parts you'll want to salvage in future or at least check for reference.
As far as the relay system suggested by Crackedback, that's would be an addition you can implement later. It uses a relay to route power from the alternator to the headlights. The advantage is a much shorter route with far fewer connections and heavier gage wiring. With most A-bodies it results in more power to the headlights and cooler wiring at bulkhead connections and other weak spots.
