Everything will swap; the entire crossmember will unbolt from the 67-72 (through to 87, actually) and bolt right into your 64. I swapped a '75 front end and rearend onto mine. This way I have 5 lugs and '75 parts all around.
Only thing I don't know about is the idler arm; it's different on the '75. It might be the same on the '67.
