Audi Repair Questions? Ask a Mechanic for Answers ASAP
You need to install the correct head in order to resolve this.
The secondary air system is more complex than you first imagine. If you simply put a port into the exhaust, you would get exhaust pressure feeding to the secondary air pump all the time, destroying it. The normal system has a solenoid valve that can open to allow the secondary air flow through. I would contact the place you got the head and tell them they sent wrong part, as it can't be easily modified. It's not your fault, it is the vendor.
OK, that was ONE of your questions- you asked about re-routing the secondary air flow straight into the exhaust.
The O2 sensors determine the flow, based on the amount of oxygen in the exhaust (because, by design, oxygen is the ONLY thing they detect, they do not analyze your exhaust, just the oxygen balance, to determine combustion efficiency, etc)
hopefully you can get this resolved
OK- I hope you are up to fabricating this- remember, the system has to be able to sustain exhaust temperatures and function thousands of times (optimally) Let me know how it goes.