Hello, I happened to read that the Dohc ZC exhaust manifolds flow better than many aftermarket ones. The only advantage of mounting DCs is the much lower weight.
Are this true^?
some people report losing performance with aftermarket manifolds. Are true?
The standard SOHC D series manifold will bolt to a DOHC ZC head but there is some port overlap that can be correct with a Dremel. This is likely why you have heard the ZC manifold flow better since it would have a proper port match.