I have a set of throttle bodies that will be going on a 2.0 zetec.

I'm wondering how you actualyl measure them?

I hear 42mm, 45mm and 50mm being thrown around but what does this figure relate to? Is it the port side maximum diameter (as its oval shaped) or is it the inlet side diameter which is circular?

Inlet inside Diameter (ID).

Thank you!!

Im also surprised at the speed of response on this site!! Its amazing!

Some of us reply slower............. Inlet internal diameter

Its the diameter internally where the butterfly sits, they generally taper from inlet end to the butterfly end.