Hi,, I have Tom's split manifolds on my project,, I had a offy single four barrel on them it fit well flange to flange,,,but the deck heights off the head surface was different, so you have to grind on the little retainers you plan on using,, I got tired of that and bought a clifford single four barrel, like said I have a little filing side to side on the flange, but the casting heights off the head deck are almost identical,, no more grinding,,oh yeah....when I ordered my manifold 4 months ago (I just got it last week),, they didn't mention the difference,, they thought they fit each other well,,maybe they are just hungry for x-mas.....C-ya
