The NV4500 is longer than the SM465 by like a couple inches. AND its hydraulic, so the bell would need to change and swap to hyrdo, the tunnel cover would need to be modified for length, driveshafts, the front would need to be longer and the back shorter. output shafts are different on the driveshaft yoke.
This is just what I vaguely remember. I think for this to work you need a early GM specfic trans, otherwise you need adapters since most were from a Dodge.