225 /6's created equal?

Pretty sure my old mopar performance manual says that all heads from a performance standpoint are the same. So basically any slant six head is a "good one". Did not even know they did away with the spark plug tubes on later castings, mine had them and they always leaked too. I think the hemi-tubes were the coolest part of the look for that engine besides the slant:)

Don't think there were many mods suggested for the heads other than milling for compression and general blueprinting. Most of the emphasis for extracting performance was raising compression, hotter camshaft, the 4bbl intake and exhaust work. The usual mods for any engine.