I've assemble several different 400 stroker motors with those heads with 1.5 rocker ratio aluminum rocker arms and 3/8 pushrods with solid roller cams and lifters
I'm getting ready to finish assembling a 1972 413 truck block bored to 4.250 with a 4.150 stroke crank with a set of their heads and a set of ductile iron RAS blueprinted 1.5 ratio rockers, if I run into problems with 3/8 Manton 3/8 pushrods on the hydraulic lifters used in this motor I'll add onto this post later about that