Agree! I followed the directions to the T and they went right in. But, the car has to be pretty high up so you can slip in the headers from the bottom.
My car is a 74 Duster with a 360, 4-speed. I did have the steering column out and the t-bars out as I was restoring the car. The PS gear box is not easy to get back in with the headers installed but it can be done. But, I wouldn't take it out and put the headers in. I had to replace mine after the fact and it was a PITA.
Also, use the bubble wrap that came in the box with the headers and wrap each tube individually and that will keep them from getting scratched. It was worth the 20 minutes to do this.
Sorry it takes some work to get these things in but the directions are good. Plus, they sound and look awesome!
