Have a look around this website. It has a few flow charts for various cylinder heads that they have machined. I don't know how good the CVH heads that they have ported are, but I know there is a couple of tuners in this country who are very good at getting big outputs out of the 1600cc CVH engine.

I know that the US (and probably Canada?) market had different CVH head designs to European cars so you may find different end results.