First order of business is figuring out what you have. '64-'66? No such creature. '64-'65 used a flanged ball and trunion output shaft and housing, '66-'67 used a 27 spline slip yoke output shaft and housing. '68 and up (including OD trannies) had 30 spline output shafts and housings.
Not saying some mix and matching can't be done, but for the amount of parts that would need to be changed over I think you would be much better served to just source a complete A833 OD transmission and bellhousing.