Have been following this thread with interest. Both the 1x2 and 1x4 manifold renderings look great. I can also understand the interest in the 2x2 configuration as well.
As we've spoken of before, a side draft 3x1 with Carter YH carbs would also be of interest, giving that "old school cool" Blue Flame look. If you take your original square radius 1x2 design, remove the carb pad on the top, and add the three carb attachment pads down the outside of the plenum across from the inlet ports, and "Bob's your uncle"! Just three bosses on the top of the plenum to mount the linkage jackshaft assembly and you're good to go.
By the way, does your CAD software help in the fabrication of the patterns and does it allow for casting shrinkage? Just curious ...
