Algon also made a set up with the stacks angled inward about 45 degrees, instead of straight up as you have pictured. I think the angled version would be better for a cobra, unless you want the stacks sticking straight up through the hood, like an AFX racer.
I think the throttle bores are 1 7/8", about 48mm. But, with only a throttle plate, and no venturi, they will flow better, about equal to 52mm webers.
I know there are different EFI set ups, some needing more sensory input than others, so I don't know if you really need a vacuum input. You would need to talk to Kinsler Fuel injection, as they make hilborn type FI systems into efi, and will take an algon, hilborn, jackson, or one of their own intakes and set it up for EFI, with filters as well.
www.kinsler.com