Small Block Bellhousing That Fits 4.8" 4 Speed Bearing Retainer

Are there any stock small block bell housings that could accept the larger 4.8" input shaft bearing retainer? Has anyone machined the small block 4.35 retainer bell to the 4.8" retainer size?

If not then I guess it is an aftermarket bell housing only if I want to run a 4 speed with this larger bearing retainer.

No stock small block bellhousing had the 4.8 bearing retainer. Aftermarket 4.8 is common. You can go the OD bellhousing route and just swap retainers. What transmission are you using? Are you sure you have the 308 bearing large bolt pattern?