In Chrysler, the hemi is the older engine by 7 years (1951 vs 1958), and the B/RB wedge is not a descendant of any hemi..
In general, the wedge (pushrods and rocker arms, closed chamber with quench, parallel valves tilted at an angle to the bore axis) only came into general use in 1949 (Cadillac and Olds, and still used today in LSX), but the Harley-Davidson hemi engines date to 1926 and every English bike mfg. had a hemi engine before WW2.