Any clutch fan options for 73 dart, /6?

Yep, this can be done. Clearance is real tight on a Slant-6 A-body, so you need a shallow fan blade and clutch setup. Not hard to pull from a wrecking yard if you know where to look. See here and here (on that page you can read up on the Toyota Land Cruiser fan and clutch — then go pounce on this ridiculously inexpensive one)