I can't believe no one would answer this.... as a general principle, when using ANY exhaust system, I make every effort to match the ports. IF nothing else, it smoothes gas flow. In the old "tuned pipe 60" days, we actually "flowed" headers, meaning we carefully shaped the port and the curve of the inlet port to match and optimize flow. We found a considerable rpm tuning difference between the "flowed" headers and the stock mis-matched, irregular interior ones.

Ain't scientific, but I believe it is a worthy effort to match them.