The old parasitic drag notion has been around ever since some joker put a 727 from a new Yorker into a Duster. Problem was, he used the New Yorker converter. A lot lower stall than a 904, hence the 'parasitic drag'. Racers run the 904 so they can get every tenth available, but for the street, it isn't worth it. You can actually drop a 904 clutch THROUGH a 727 clutch; there's that much difference in strength. Just a bone stock three clutch direct 727 is twice as strong as a 904. In my 37 years rebuilding them I've only seen one blown sprag; and it was in an old New Yorker being driven by a senior citizen who got stuck in the snow. Hopped up 904's are good for making a ton of money for rebuilders off people who are afraid to cut their driveshaft.
