Just to toss my nickel's worth in here: I can tell you just from looking - those are Oldsmobile 350 heads for sure, not Chevy, and they will not interchange, engine to engine. The heads you have use a non-adjustable rocker arm setup that sits on stands, one set per cylinder; easy to set up, as there is no adjustment needed - just bolt 'em down. I don't know exactly when Buick-Oldsmobile-Pontiac started using the "Corporate" (read Chevrolet) V-8 engine, but it was sometime in the early to mid '80s.