Hi Enoch,
I'm also juggling with the I4 8v DOHC engine position. Trying to get the right balance with the engine height regarding the sump protrusion and bonnet clearances. Reference the inlet manifold, I've got some CBR929 throttle bodies. This will entail chopping the manifold and grafting on stubs to match the throttle bodies centres. This will be quite a way ahead in my schedule! Still interested in how you get on with your plenum mods. Could still change my mind and still use the existing plenum in modified form.
Cheers
John