Dougs D-453 headers and 727 ?

I was looking at the catalog on the pertronix/dougs site at the D-453 Headers and the footnote says does not fit with 727 Trans.Anyone running these with a 727 trans? Any interference issues?Also why do they not list the '73 -up Darts? I would think if these fit a '72 they would also fit a '73 .I'm asking cause I have a '73 Dart-'72 K frame 360/727 and I would like to run these headers but not if I'm gonna have fit issues.Thanks in advance for your reply's .

http://www.pertronix.com/catalogs/pdf/dougs/2010/dougs_2010.pdf