There is somebody selling the B&B 1.6 high lift INTAKE rocker arms for the later 235/261 on Ebay from time to time. Too bad he doesn't have them for the exhaust side where you need it...
As I see it currently, when you consider the low RPM potential, and poor intake valve to piston clearances on a 216/236/261, I'm wondering just how much benifit you're really going to get out of a roller cam without first switching to a 12 port head with better valve train geometry??