I have the r/h port done ready to test, it's 39mm wide, if it's not measuring 178 through the carb I'll go wider on the outside as it's easy to patch between the fins. I'll have to watch just where that stud is though. This is another old head that had 44.5valves and 38mm ports. Ben's 750 has that size but is better shaped and flows much more. I can swap his head with the 34pwks and it should pull better, and I don't think maximum flow is much different.
I'd like to know what the Westlake/Rickman 8valve heads flow, the modern Triumph 4 valves are 181cfm.
On a triple, though I no longer have one, I'm pretty sure those studs are very close. The triple heads are definitely not that cheap or easy to get.
This is that 38mm carb head, it would be interesting if I can get it better as it's going to be near the valve that is the limitation. If this flows more the speed will go up.