I was hoping someone would chime in but can offer this much. .
Roofs should be listed in most Hollander Interchange Books...look in the body parts one. . I have the 64-74 set and of course haven't seen my body one lately but will look harder for it if nobody else can come up with one. .
A lot of 50's/60's and early 70's cars have different w'shlds between hdtp and sedans. . I believe it's because the A-pillar heights and angles are different so be careful if you're needing to include the A-pillars. .
Depending on what exactly you're proposing and if a 2 Dr. sedan is what you're into, a 4 Dr. sedan roof may work. .
It'd be easier to know what exactly you are doing...do you have a '67 Hdtp and a '66 Sdn parts car or what? .
As you probably know, with some exceptions other GM division shared body styles often work...like 66-67 Skylark, Cutlass, Lemans etc. .
Lay out more exactly what's up and again I'll try and come up w/ my Hollander book if nobody else can first? .
~ Pete