i made some 750 gsxr throttle bodies fit my old mk6 escort, they were 42mm and tapered to about 38mm i think.

i can measure these if like and let you know. provided i can find them in the garage lol
i dont think they are much if any smaller tbh.

iirc 40s are best for a 2.0l? and 45's are too much?

i may be wrong tho, it was a good 3/4 years ago since i was dabbling in carbs lol