Depends on what size front bearing in the overdrive. A/F O/D's could have had 307 or 308. 307 bearing we simply change retainer. 308 bearing, and we need to machine the retainer to 4.805" and the bell to 4.807" to fit the 2 together. 308 bearing will be C13157 casting number on the retainer, 307 would be C97728.
