Technical Ford transmission experts. Help ID a part.

Need some help here ID'ing a what I believe to be a ford transmission input shaft part. This will be going into a sprint car in/out box. The one pictured puts the spline even with the face of the in/out box. Was this custom made for this application, was it stock in a ford transmission??
Need to locate 1 or 2'of these.in either 6 or 10 spline. Thanks all in advance for your help. Jay

 

That will be a "custom made" piece...No stock Ford box will have one looking like that.

 

Looks like a mis-aligned industrial application part....IMO

 

Someone took an input shaft and shortened the input splines and ground off the gear that drives the counter gear. They also took the bearing retainer and cut off the sleeve for the throw out bearing. A that is left are the syncro teeth to allow engagement with the shift collar. Poor man's home made in and out box. Lots of work though.

 

The "gear" missing would not affect usage of this part. A lot of the sprint car and supermodified folks used truck parts. I'm thinking that's where I may find this. After all the in/out boxes used ford guts. Search continues. Thanks all for your help