throttle body size ?

[nuclearr]

I have several throttle bodies laying around I need to know the proper way to measure the throttle body to know which one I have. I have a unknown tb that was given to me was told its off a galant 4g64 but it seem bigger than my 96 galant tb.

 

[Absit]

You measure the inner diameter of the inlet (and outlet, some TBs differ here).

 

[bradselph]

My stock 4g64 TB was 54mm