I need headliner bows for a 74 nova and not sure it I can just use bows and clips from a 68-72.

Just use a one piece hard plastic type. I know thats what came with mine originally.

1968-72 used roof bows. 1973-74 used card board roof liner insert. Check www.chevy2only.com (http://www.chevy2only.com) for description.