this is the description of the manifold: This manifolds is made from the Highest Quality E316 STainless Steel, which makes it much stronger than E304 stainless, but at the same time the material's properties make it more flexible than E321 STainless, thus making it the best & most used choice for motorsports applcations. This manifold is made to fit the stock EFI pipe & retain the oem TMIC, its piping is 32mm wide & 2mm thick.