I have the throttle body off my car and it looks like it would be stock. But what i question is that it is stamped "MPFI Rochester Products" It doesnt say GM anywhere on it. Is that normal? Do they all say that?? I am not sure how to measure the throttle body but i measured one of the butterflys end to end and it was right at about 58mm. I am pretty sure its stock but does anyone have any input???

 

Yep, stock, rochester (makers of the infamous quadrajet) has been making fuel components for GM for over 30 years. Hope this helps, Prorac1

 

Yea that helps, cant say i am really dissapointed, i hear they dont do much anyway. But how do you go about measuring a throttle body?

 

Like since the 50's or maybe earlier.


Are you sure you did not measure 48mm? I think that is the stock size.

 

Where does is say that? My stocker just has the part #'s on it, and "Made in USA".

You measure the inside diameter of each individual bore, where it connects to the intake manifold - that would be the same as the blade diameter. 48mm. If you measured the height of the oval that the bellows attaches to, you might get about 58-60mm, but that's not the "size".

 

48mm is stock...injuneer is correct you measure the inside diameter.