NP I think made both size front bearing retainers for both the 23 spline and 18 spline tranny depending on what year the tranny was going into, I THINK
I've ran into that years ago doing some work on a customer's 4 speed car swapping the stock bell housing for a scatter shield so he could race it at some tracks in SO CA years ago
Another option is to use the adapter ring from the scatter shield so you can use the smaller front bearing retainer in the larger hole bell housings