Fast Fred is right, just remove the humps, good alignment, etc. The slight roughness on the surface helps keep the fuel/oil layer from building and causing some flow restriction. The slight rough surface promotes the fuel/oil layer to break up. Take a piece of wet type 220 sandpaper and place some fuel/oil mix on the paper and blow parallel to the surface, then do the same with a piece of glass, you judge what happens. Ever notice the inside of auto performance intake manifolds, rough cast, we would just do port to port matching and gasket alignment,and trim, remove sharp corners when we were into 1/4 mile drag racing and oval track racing.

On my 25ss engine with the aluminum reed cage with 8 holes of 5/8" x 1-5/16", KC16A carb, long stops and reeds set at 3/16" open the least flow area is the carb venturi. If the 3 -5/8" diameter intake ports are considered they are the smallest flow area. But when considering the twist and turns of the flow from carb, through the inside of the reed cage, then the sharp turn from inside the reed cage through the cage openings, past the reeds, flung around with the rotating crank, then into the intake ports to the cylindere you have some very convoluted flow dynamics the least of which are polished surfaces. Need a flow bench to really find the major areas to improve then test and find something different, Ha!.

Long time ago (in a galaxy far far away) I took a 22 ci block to a milling machine and streamlined the intake ports like the ramp design to input bullets on the old side loading Winchester rifle, rounded corners on the ports. Didn't help a bit. Exhaust porting was the deciding factor there.