Hi Jim,
Those extractors (as called here in Australia :wink: ) look nice don't they. If I could offer some advice,..it is actually not a good idea at all to port match the exhaust headers with the cylinder head exhaust ports. My understanding is that is the very best way to lose power, especially through the mid range. To see an improvement that might otherwise not be evident is to ensure that there is a mismatch at the top of the ports while the base of the ports align as evenly as possible. A few mm is all that is necessary, so if for example the cylinder head exhaust ports are 30mm in height, then the header ports should be at least 32mm in height.
Ron.