The 122E damper is thicker than a standard 440 damper so you need a shorter pulley. The Doty lower pulley should line up with a single groove top pulley or you can use a Hemi lower pulley and shim it a little bit.
I was always under the impression that the lower pulley was the same on all big blocks, it's just the 69-71 upper pulley that is shorter in depth as the balancer was thicker?
It looks like where this one is will line up perfectly with the 69-71 hemi upper pulley, in the process of trying to acquire one now.
