Help me to identify this trans

krazykuda said
'73 Slant 6 in a D100 or D200 with the long extension (I believe that refers to the tailshaft).

http://www.mymopar.com/downloads/transguide.pdf

I was just coming back to make a post, yes........3640081..........225..........727..........truck, long, heavy duty

Found here if that helps anyone else http://board.moparts.org/ubbthreads/showflat.php?Number=3220758

Heavy duty, does that really mean any difference over another 727, I ask cause I am going to have it gone thru, should I be getting a heavier set of clutch packs ect, maybe I need to clarify this with the re-builder