Missed on this combo?

I agree with the BLP carb. They are worth every penny they cost. You could use a B4X in whatever size Joe tells you. They are very nice carbs.

It went a bit rich up top. You might have opened the main air bleed up a bit. Or, opened up the bottom emulsion hole by .004 and see where the BSFC went.

I agree it's a bit down on power. What did your machinist not like about the exhaust port?

Unless the exhaust port is absolute junk I think I'd rather have a single pattern cam. It could use some more duration on the intake side. Or try the cam at 108. It will close the intake later and give the cylinder more time to fill at higher RPM.

Defiantly big on the BLP carb. Google B4X 4150 carb and look at them. Work of art.