For the 216 and early 235 there are Barker's (intake only)
Rocker Post circa '04 Fenton also made a high lift rocker for the early engines.
Less known is company called Thomas that made adjustable rockers for alot of different engines. These show up on ebay once in a while. Problem with them is that they are made of magnesium - which doesn't age well tending to get brittle.
