<VV> 64/5 transmission mainshaft/input

[Bruce]

I just bought what was supposed to be a 64/65 4 speed transmsission, but my 14spline 66-69 input shaft (I know it's longer than a 64/65) won't even fit into the mainshaft.  The inside diameter of the mainshaft is .675 and the splines on the input are .712.  Even the diameter of the shaft is larger than .675.  Is there a difference in the diameter of the 61-63 transmission input compared to the 64/65, as well as the difference in number of splines, 12 or 14?  Do I actually have an earlier 4 spd rather than a 64/65?  Or am I mistaken in my thought that a 64/65 14 spline  input shaft should be the same diameter as a 66-69 14 spline shaft.  I'm trying to use the 66-69 input with the 64/65 transmission in a Kelmark mid-engine conversion.
Bruce Tester