Actually these Hedman Elite 1-3/4 headers I put on my 63 in 2006 have been great and trouble free. Thick flange and zero leaks. But I just ordered a set of TTI 2" headers for my 63 to go with my new eng I am building. We have the TTI on my boys Dart and they fit good and hold up very good as they have been on his Dart about 10 years and are holding up great and they have very thick flanges.
So I say if you have the money the TTI are a very good header. The Hedman Elite are also a good header but not as nice as the TTI's. I have never used the Doug's but I hear they are also a great header. Ron