Slant 6 head interchange: 1975 head on 1969 Block?

Are they the same lame rocker arms that are used with the solid lifter setup, which suffer from ratio-droop (1.37?) or are they a different design which might actually HAVE a 1.5:1 ratio?

If they DID, I could use them and some adjustable pushrods to achieve proper valve lift.

Any chance?