68 383 complete engine

even 2 bbl 383's had 906 heads in 68, magnums had the 440 hp cam, springs, hp exhaust manifolds, windage tray, 67 915 heads came with both 1.60 valves and 1.74, the 1.74 were in the HP car models, and the 915 heads with the 1.74 valve will usually have a HP stamp on the ends of the head.