the isky 1012b was the '64 s/s wedge race cam; 320 degrees duration, .520 lift, 108lsa, a lot of cam. the 1012b was superseded by the racer brown stx series; stx21, 22, & 23. the ssh25 and 284-.484 are identical for all practical purposes. the real issue may be how much head modifications your willing to do to run a high lift cam. there are 114lsa versions of the 284-.484 and 292-.509. in my opinion, none of the above.
The "hemi grind" was available through all of the 70s. It had 284°/284°, 0.465" lift and 60° OL. I don't know when the rest of the "purple shaft" DC cams came out, but in 1976 Ma Mopar was still recommending the Racer Brown SSH25 and SSH44 hydraulic cams. I tried one of each before I went to a Crower solid. My buddy was running the mini-express with mushroom tappets. That thing was Bad Azzzz.
