Nice score! I had a 78 D100 SL6 3 on the tree about 15 or so years ago. It was very difficult to keep up with traffic and the slow shifting a 3 on the tree requires made it even more difficult. I have a feeling you'll be swapping it out sooner than later down in socal.
That is definitely a concern. I want to drive the thing and not hate it, or be a nuisance to traffic. Which here is 75-80 mph. And on top of that, I have a mopar crate 360 and a 46RE sitting here built and ready to drop.