Curious why you want to kick a 36,000 mile car in the head, but I'd use EVERYTHING from the Dart if it's a disc brake car including the spool mount K and electronic ignition. Even if it's not, the motor/trans would make for a sweet running everyday driver. Ebrock Performer and mid 70's Thermoquad added in when you got around to it would make for a nice upgrade on the stock two barrel without ruining fuel mileage.
Pull the original motor/trans out, crate it, and stick it under a bench in the garage. That way if you ever decided having the car numbers matching was important to you, you could rebuild and stick the original drivetrain back in.