AFMM3 - as I understand, your dad's Dyna is a pre-'06 model ... I think the '06-later transmission top cover might allow the Softail setup to work ... I posted some photos demonstrating it on a thread about true duals for Switchbacks (
https://www.hdforums.com/forum/dyna-...-duals-10.html) ... I am almost certain the transmission top cover on mine ('05) would NOT allow Softail duals to work ... but, I would really be interested in seeing if an '06-later is still a possibility ... you should see if he'll send you the pipes and try it out on your '50th anniversary Duo Glide' ...