Did D.D do any of their own turbos or were all sent out for that, how does one know if they are DD .?
I'm guessing what your asking; Did they mfg their own turbos? Of course not. Do they repair their own turbos; probably not.
DD 71s, (53s, 92, 149s and others) were sold complete with Turbo and inter-cooler, yes. Other companies would also purchase DD engines and soup them up even more with larger turbos and injectors for the high performance consumers. Roger Penske put an end to most of this abuse. Still not sure what your really asking for.