354 Hemi , it was so far ahead of its time , the competition was the ford Flat head V8 & the Chev straight 6 , Actually Caddy had about the closest engine that was any competition to it in the early 50s
440+6 , Street warrior , generally quicker than the Hemi in short street runs , very driveable , decent milage & the flat powerband that just didn`t stop pulling
426 Hemi ..... obviously stock it was not particularly awesome & the early solid cam version makes more sense But it re-wrote all the record books made far more power then the Production verson with relatively minor changes , & to this day still dominates all top Fuel classes , is banned restricted or penalized to make anything else seem competative in most racing classes & has the looks to boot.
bottom line is virtually all Mopar engines are awesome , none are particularly weak engines with achillies heels , all can make awesome power with great durability & generally far better efficiency . Mopar engineered the drivetrains extremely well up until the K car days