Two aluminum throttle bodies side by side comparing bore sizes

Side-by-side comparison of two cast-aluminum throttle bodies standing on a towel atop an appliance, viewed from the mounting-flange end to show the difference in bore size. The left unit has a smaller bore with the throttle plate removed, while the right unit shows a noticeably larger bore with its blade in place.

AI caption February 2004 · Photo 12 of 5000