No factory input shaft, one trans [ 1.68 gear] has a Rossiler PG input, the other [1.76 gear] has a PG A-1 input.
One thing of interest is Dean Carter JF , B/nd, A/nd bought a used trailer a few years ago from a Comp racer, and it came with drawer full on different input shafts, like 16-18.
Different oil holes, grooves, and in different locations. The Comp racer was using them to fine tune his converter.
I've heard some blower racers use the 400 turbo shaft.
Jon