I have contemplated this swap myself in my 65 Dart wagon with a 273 but decided to use and save some money with what I have on hand - a complete V8 65 833 setup.
From what I have learned, you’ll need the complete AX15, bellhousing, flywheel, clutch slave and clutch master cylinder, probably the driveshaft to shorten (or at least the front yoke to mate with your driveshaft), back up wiring to mate with yours, possibly the truck clutch pedal (little hazy on that). It will Bolt to your 273 no problem since the Bolt pattern on the bell is the same as a LA. And of course modifying your trans tunnel. There are several threads on doing this conversion so do a search on it. Hope this is of some help!
Edit: the Passon 5 speed would be the way to go if he were geared up to get them in some semblance of production
