340 in a 65 Dart, TTI HEADERS, H exhaust

Any further comments on using headers on the 340 in my 65 Dart restoration. TTI is where I am headed with their H exhaust. Any comments? Any advice? Any tips? Any anything to put me in the right direction....at least I think I am going the right way, buy have not ordered them yet....but soon. Any help before I order the parts would be helpful. Other people's experience is always the very best guide. Never done this exhaust before. Thanks. Old Dart 66