Transmisssion braces needed?

How important are the transmission to engine braces on A bodys? We are having a devil of a time installing headers on my sons 73 Dart Swinger. There is not enough room to install these things between the header tubes and the engine. I only ask because we have been working on this for about 3 days and I have walked away, drank beer, cussed and thrown things and it still wont work. I have worked on Chevys a lot and they don't have these dang braces to deal with and there seem to be the same number of bolts that go through the bell housing so I am wondering just how important they are. OK, you can all start blasting me now:) I appreciate any help you all can give because my son loves Mopar and I have a feeling this isn't the only one we will be working on. Thanx, Kevin