Have you thought the tranny mount missaligment "problem" could be on K member somehow moved ? Or some unybody deal?

Andy, both if those mounts are the 1970 and later style, not like your Coronet came with
The OEM trans. cross member should have a rectangular section welded onto the rear of main part that the OEM tranny mount slides down into with one or two studs going through the bottom of the mount, depending on the year and trans type
I think Mopar started using that later type mount in 1970 on the E body and maybe on the trucks, vans and B bodys

This is on the Duster and it has the late model spool mount transmission crossmember. I feel like I figured it out. The new poly mount lines up in the correct spot so I'm good to go. I just ordered the new driveshaft since I now have the transmission in the correct spot.

I'm not sure where that trans mount that I had came from but it might have been something left over from the '77 pickup truck that I rebuilt a few years back. The mount might have gotten into the wrong stack of parts and confused me when I put the Duster back together.

I'm glad you got a handle on it