I replied to your ad over at Ford FE forum.
I have a pair of said exhaust manifold that I will part with.
When I bought them in '80's, the driver side was cut for clearance(?) and steel plate welded in place (does not leak).
I had 68 GT 390 Scode mustang fstbck with PS n PB. I replaced the 390 with a dual 4 bbl 427 TP and I used the Fairlane exh manifold.
Ken