Need complete bracket set for 455 going into 69 GS 400 convert

Thanks for the help. Here is the article I found in researching the issue. If I am understanding it correctly,
the lower aluminum bracket is a 1231871 or 1387208?

http://www.buickperformanceclub.com/455pulleybrkts.htm

 

The first and small aluminum bracket is the center bracket for the power steering ,67 to 70. Those are all the same for SBB and BBB,part #'s might change,but they are the same. The outer 2 steel brackets ,the SBB and BBB are different.For the SBB they are still some around,for the BBB not many,but those are made by the aftermarket.The bigger aluminum bracket is the AC and alternator bracket for 1967 to 70.That's the way I remember them.Bruno.

 

Thanks Bruno, I'm slowly piecing it together