Here's where the tedium starts. Twice as much work today as any other day with the least visible results. There will be a LOT of days like this ahead. 9.5 hours work today.

Tools used:
I did find a need for some 1/8" shank tools today so I borrowed a 1/8" and 1/4" HSS (high speed steel) ball burs from my Dremel supply.

This pic shows I went around and radiused all intake right side intersecting walls that have a sharp 90* angle. First dressing them with the 1/8" ball then finishing with the 1/4" ball. Inside of primary intake ports were only done with a 1/8" ball as thats the closest fit for a mildly radiused corner in such a tight area.

All of this is far from complete as I will end up sanding smooth and feathering all edges to eliminate the sharp contrast between start/stop points by blending in those areas when I move to using sanding cones and cylinders.

Notice the difference in the two bolt holes on the trailing edges of intake port one and two (left-to-right) in pic. In the last pic in this series you'll see how much more rdiused they are than the square-shaped ones in the last pic. Also the radiused inlets in each intake port compared to the sharp, 90* corners in the last pic.

It's worth noting that this is "rough-cut" work and in no way represents the finish quality of where we'll end up. Over the next 3-4 weeks this will take on a much more smooth, radiused and polished with much more gradual transitions from plenum area into the intake ports. Gotta grind before you can polish and smooth.