Hey--I'm right here in town with you & I've seen your car around! It's sweet! I've got a pair of Satellite wagons & a Duster. One of the Satellites is a '74, maybe we should get together and hunt parts.
I used to have a '74 Roadrunner, it broke my heart. What color's your parts car? There's not a lot of interchange with interior parts. I think the kick panels are the same, dashboard and gages etc. of course... steering column probably.
Maybe rear axle... Of course engine, tranny... driveshaft probably not... just about anything under the hood yes... Anything related to the front-to-back wheelbase probably no... glass, probably no... Bumpers of course not... Gas tank I think yes... brakes of course yes... T-bars yes, springs yes... K-frame yes... did I miss anything?
EDIT: Of course I did. None of the sheet metal will interchange, neither will the grille and light housings. Marker lights, of course, interchange with about everything from about 1972 'till about 1990. For some reason the red marker lights don't hold up as well as the yellow ones do. I've pulled those off Horizons, no foolin'.