I have sent a bunch of questions to Sound German. I have only good experience from ZF transmissions so it will be interesting to hear what they have to say about NAG1 compared to 8HP70.

70 W100 Power Wagon. 318 4-spd
70 Sport Fury 440 2dr HT
71 Duster 340
71 Charger Super Bee - 383/727
72 Charger "Sabotage" - 440/727 - Street/Strip
78 Warlock in beautiful patina