Dart IRS

HawaiiDuster, do you have any pics of the unit. Mine is under the 300C on a trailer and doesn't move well, car is sort of bent in half. I have looked for illustrations of the unit, which because it comes out in one piece like you said, could lend itself to retro fit but haven't found any. Just remember commercial with Dr.Z.
I have been looking into track, ride and jounce info. What I thought was cool is that it's all mopar. Maybe it's a pipe dream but for me the parts are free.
I had an XJ6 a long time ago and I liked the suspension especially the inboard brakes and low unsprung weight. But the center looks like a dana 44 the size of the original dart diff.
The 300C stuff is designed to work as a package with the 5.7 so if it could be shoehorned in it would require less engineering.
I was hoping that with all of these ending up in the junk yard and not much need for them in the original application someone would have done the math so to speak already.
I'll keep looking.