Pre-'67 Slants won't work with a 67 up auto tranny as far as I know (unless you change the crankshaft to a 67 up crank). You will want to get a 67 up Slant to work in your 72. There is one in So Cal from a 72 Dart in Craigslist right now for $300 (Slant 6 for sale). Maybe get it for much less if no one else is interested.
