Most "old school" turbos (that I've had experience with)did not have waste gate pressure control. The turbo was designed to only produce a certain amount of boost, and on a Detroit the turbo and blower had to be matched. In the mid seventies, my dad added a turbo to a non-turbo 8v-71 in a Road Commander project, but he had to change the blower when he did this. He told me that it would over boost with the original non-turbo blower once the turbo was added. I though that maybe you had found a late version 6v-92 that used a waste gate control like many modern engines (wasn't being critical by no means) your work is incredible.