Never assume ;-) It's a 73 that had a /6 but I have replaced the crossmember with a V8 A-Body frame from a 70 model.
Johnny Dart - Thanks for posting those pictures, I will be using the correct factory brackets for the final installation, but those pics tell me that I can just drill some holes in my B-Body brackets to mock it up. For now, I just need to get the engine and tranny in place so I can figure out what modifications I need to make to my shift linkage and kickdown linkage to accommodate the headers. Its a column shift automatic.
But I would still rather find the correct brackets sometime soon.