I have this 1973-74 E-body transmission crossmember that I would sell for $79 + shipping.
If you are looking for a mint one, then the one I have is about as good as they come.
FYI, there is difference between all of the Cuda and the Challenger side glass stainless trim pieces.
You will need to research if any pieces interchange between the two models.
Not surprised to find examples of the earlier style weights on 1970 models.
This might be some sticker shock, but I just fond this on ebay.
https://www.ebay.com/itm/203746860454
Here are a couple of pictures of the original passenger side manifold off of my 1969 Dart GTS 340.
I also dug up a 1970 and later heat rise counter balance. The 70 and later ones were thicker and the face was different.
Those manifolds are from a 1969 A-body 340. The manifolds above are very nice and would work, but if you are splitting hairs and truly want the correct 1970 dates and appearance, then you might want to keep looking.
FYI, there was no special AAR or T/A exhaust manifolds. All 1970 340's had the...