Newer Aluminum W/P on '65 273 with A/C

You will loose the view of your timing scale also. I think your ac compumper has idler and tension pulleys and a single V belt. Thats where your real problems will be. Not easy to change there line up.
You might be better off just buying everything from the block face forward to the radiator support from a later LA. That would put the compumper under a matched pair of V belts, delete the little pulleys, and all those other conflicts.