Hi,
Just an opinion.
I think that those bike TB are not the best way for the Zetec engine.
Check the position of the injector at the Ford manifold, they spray exactly at the inlet valves.
I have a sectional drawing that confirm that. At the other hand the TB of the bike will never locate the injector correctly.
On top of that it has a lot of parts that can goes wrong and also are difficult to balance.
So I will advice if you haven't buy the TB jet to reconsider the setup.
Make a inlet manifold wit a single TB will give you the same performance although most people think that complicate things is better.
The initial problem arise from the available space in some kits, so there are solution to solve that problem without go that difficult way.
As an example I post some picture of a Opel engine with such manifold.
Just 4 trumpets with the injectors located at the right spot, those protrude the main plenum, underneath the trumpets there is a slit that communicates with the inlet plenum [distribution plenum] and at the front the single TB.
Easy to fabricate etc. the rest of the components like IAC remind the same only it needs to bypass only one TB.
Some of the TB have the IAC integrated in the cast and an very small.
Here is the picture of the Opel inlet manifold, but we will use the Zetec 2.0L engine in our build. [Change the plans]
I haven't finish the Zetec 3D design that is why I could show you the same idea but at the Zetec.
But here is a picture of the Blacktop as far I am on the design.
Regards,
Cobra289