You're in for some conversion mods of some sort. The OD trans has a large diameter front bearing retainer. That means it needs a bell housing with a corresponding large hole. The '65 bell housings all have a small hole, so, if you're going to use the OD slant 6 bell housing, you will have to rig up the clutch release linkage parts to fit the car. That wil require a custom bracket for the Z-bar pivot ball on the bell housing to line up with the stock one on the frame rail. Your original flywheel and clutch assembly should work ok, just match the release fork with the bell housing (and it's mounting design) you're going to use. There are other methods to skin this cat, but, I found this one to be the easiest.