Mine is also tight as mentioned by the OP on both the 72 Duster and the 69 Dart...
In looking at the above pics the bracket in the first picture that bolts to the trans is different than mine...
Mine does not have the offset which relocates it forward...
I suspect that may be the same problem the OP is having...
Both my cars were /6 cars with 904's and the crossbars and all linkage and brackets from the slant six cars were re-used when the 340's went in...
It can be made to operate fine but it is tight...
I searched all my pics but had none of that linkage...