I think the rooster comb on the VB needs changed for the 1 wire NNS.

they have a valve and housing to add PTK or a valve and housing off of a early 904 VB like I have. (grabed the PTK valve at the JY, but never used it yet)

I cant say for sure if it is as ez as swaping in the 71 VB and have it work though.

I will dig that valve and housing out later and post a pic, i read about this in a mopar muscle mag a few yrs back.