Just got the Dart header and exhaust done!
Mufflers are made by Goerlichs and are single chamber.
Yes I have power steering and automatic tranny (904) The fit and clearance is amazing. You can def tell that Dougs knew what they were doing when designing these. The only thing I had to change was the starter which I knew ahead of time. I love that they dont drop too low like some other headers so I still have plenty of ground clearance.