I have found lots of discussion about matching an oval port head to an intake with d-ports, but not the reverse.

What are my options for port matching a 1bbl (which will get a 2bbl carb and adapter plate) round port intake to a D-port head? There isn't quite enough material on each port to match exactly, but is my best bet to mirror the D-port shape and open it up as much as possible? What additional work would be advisable on the intake?
Additional work will be done to the head, etc. to make use of the increased flow, but I'm just curious of my options at this particular connection.
Thanks!

 

did you ever get this project started? i'm thinking of doing the same to mine.

 

All I ended up doing was slightly opening the bottom corners of the intake side to approximate the D-shape of the head. I didn't open it up any all around.
I only did it b/c I was doing a full rebuild. Not worth the effort if on a currently decently running engine, IMO.
From my research, if somebody is doing a full performance high-rpm build, there are plenty of aftermarket intakes (or used boat intakes or ported efi lower intakes) that would offer much better bang for buck.
I stayed close to stock b/c I've decided to swap something else in sooner rather than later and wanted to minimize cost.