"I have heavily massaged MOFOCO 044 head ports (mine are “D” shaped and taken almost to the limit) and my CB Perf. Manifolds (I run Dellorto carbs) were not port massaged at all, mostly because I didn’t order them opened up, nor did they ask what the head port dimensions were.
Fortunately, there was a LOT of meat in the manifolds so I could grind/polish them out quite a lot. QUITE a lot. To start with, the manifolds were essentially the same size as stock ports on both ends, requiring a lot of grinding. It would have been super-cool to have one of those hydraulic honing systems with the grit slurry, but I wasn’t that lucky so I ended up using a tiny Dremel and/or cable driven die grinder and just went at it. They are not perfectly matched, but once bolted together you can’t tell from the outside, right?"
The first thing I ever did as an automotive enthusiast was porting and polishing my Austin America's BMC 1275 engine's heads and manifolds with a grinding wheel and a Black and Decker drill motor .