904 transmission installation

I believe the speedometer drive is different on pre-66 904 trans and I don't know if an adaptor is available. Imperial services is one place to see if an adaptor is available.
The 904 is an easy trans to rebuild, just buy a rebuild manual and watch your clutch clearances. As far as the kickdown linkage, there is a procedure in my old Motors manual that explains it, but it is lengthy. It sounds like you may need to lengthen the rod which goes to the trans. I'm sure someone on this board knows the '65 linkage to point you in the right direction. I put a manual valve body in my 66 so I am of no help!