Anyone know of the best way to balance each of the butterflies so they open up together and allow air to come in evenly?

Got these ITB from a 20V 4AGE and prototype manifold to bolt up to the B series heads.

Ive been trying to balance them by using Vacuum but its so damn hard to do...

Any ideas?

 

Find a shop that works on older Alfa's or MG's they have to sync Webers or Su carb's all the time and it's yhe same as syncing ITB's, a good ear to hear the vacume or one of the carb sync guages is good or find a shop that does multi-carb motorcycles, they can do it.