Yes they are 1.72 rocckers arms, they should swap with no problem, but you will need to grind the baffle in the valve cover down or replace them with aftermarket or Cobra valve covers, or they will hit.
Yes the install is a straight swap. I just installed them on my 78 Cobra but haven't dyno'd it yet. If you haven't baught them yet go with the Crane Energizer kit (PN 4474616), there identical to the Ford Cobra parts since Crane makes them both. The best price I found was Kragen who had them for like $140 for the complete kit.