Those manifolds are shite mate I bought the same one thinking stainless hmm must be ok but exactly the same as u it didn't sit flush onto the head and it started leaking within 300 miles. Problem I had is that my cars not my daily driver so it took over two months to do that milage and when it started leaking and I contacted them, the reply I got was "sorry we only warranty 2 months on our products, try fitting two gaskets that will seal it up" So I bought two Toyota gaskets took the old one off and surly enough it was fucked, replaced it with the two new ones and it sealed it a treat, 100 miles later witch actually made the manifold 400 miles old it cracked! Blokes a tosser send it back before it's to late mate