First of all thanks to all people on this forum for the inspiration and good ideas.
I decided to make a new bench and use some parts from the old one.
The frame and chambers is in steel easier to seal than any wood material (I am not a friend of wood it is impossible to weld and always get to short when it is cut).
It is an intake/exhaust bench with two fixed orifices that gives me three ranges.
Still same 12 motor setup but now as a module separated from chambers.
I did also learn the hard way that ametech blowers is rated at 60Hz and we use 50Hz
So I did lose 20% of rated capacity.
Next step is to make a new blower box with 16 blowers that will put me over 1000cfm
Still use FP1 and now with Air Flow Control Valve.
Pictures at
Erik