I assume you're looking to set your Dart with a BB in the stock location?
This might be off the wall for what you're looking for, but with a "modified" street car, suspension/tire size, I just set the front end height to what worked and was visually pleasing to me, and just had my alignment guy do his thing.
I actually used to jack mine up & down depending on my mood & what look I wanted at any given time...Hey, it was the 70's...lol!