The next adapter required is to bolt a 351C intake on to the 400 with the taller deck. I researched and found out that Weiand at one time made a adapter but as far as I found out it is discontinued.
I decided to go with this company
http://www.pricemotorsport.com/
This will allow me to use one of the 4V manifolds I already have. Here is a pic from their web site.
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