4 spd input shaft

You are gonna have to be more specific.
Are you just looking for a stump, like a line-up tool? Or do you need a working one. If yes on the latter, then you will need either a tooth count or an application, such as, for the; 2.66low box, or the 2.47low box. or the .73O/D box, etc. There are at least 5 different ratios that I have found, and I think none of them share input shafts. Low gears is another story

And, of course why? Are your splines twisted up? Or?