[Jac Mac]

If you have reduced the venturi size to around 28mm thats about the same size as a 1 3/32 bore venturi in a holley 465cfm carb, now obviously the holley & webers wont flow the same amount of air per bore, but it gives you a ball park figure to think of, Now you essentially have two inline holley 465's with 1 to 1 throttle linkage & all eight barrels opening at same time, a progressive throttle linkage is going to help. With each dumping into one long plenum for each bank, Im not sure that your 'mid plate' is the best way to go as it will favour the end cyls, also remember the impulses for each bank are uneven due to the firing order, it might work better if you were to establish a 180° sequence in linking up the individual runners & reduce the plenum volumes. An individual barrel extending down from each weber throat toward the port each throat will service might also help if thats feasible.

Interesting I'll let you nut it out though