won't go in gear

Well i got another possible cause, If it is a conversion from Auto to 4 speed, and u are using pilot bearing and not a bushing it happens to me that the steep transition from the pilot bearing to the splines are pushing against the pilot bearing making it bind there, like it was a too long of a input shaft. if that is the problem go and use a bushing and dont forget to test fit your imput shaft in it after installed in the crank shaft cuz sometimes they tend to shrink a little, and need to get honed to fit properly.