I am half way thru building a chrome set of shorties for my 55 bird, they cheap , but a little time. Used 1 set sbc chrome shorties of ebay  , sectioned the main flange . clamped, bolted and spread on to y block header flange . Welded and drilled it. Fits perfect. I will put more if ther is an interest. Just did a full layout , it would not post.  

Po ol Davie

Sparta , Tn.