Here's our set up on a 71 Valiant. Originally a 318 A/C car, now a 360 non A/C set up.
We have the other style ps pump, and I notice that your shaft/nose between the pump and pulley are much longer than ours. That may be the cause of your problem, maybe you need to find one from a v-8 that may have a shorter nose/snout on the front of the pump for the pulley.